Untitled Flashcards Set

CHAPTER 1

The biography A Beautiful Mind describes the fascinating life and experiences of mathematician John Nash (Nasar, 1998). The powerful story was made into a major Hollywood film that won the Academy Award for Best Picture in 2001. John Nash was a remarkable figure who received a PhD in mathematics from Princeton University and taught at both MIT and Princeton. In 1994, Nash won the Nobel Prize in Economics for his work on game theory. From what you just read, you would probably assume that John Nash had a very productive career, and in many ways he did.

However, there was another aspect to John Nash’s life that caused considerable distress to himself and puzzlement for others. One day at work, when he was 30 years old, he walked into a room full of others in his department, held up a copy of the New York Times, and said to no one in particular that the story in the upper-left corner contained an encrypted message. Not only was it a message in code, he claimed, but it had also been put there by inhabitants of another galaxy, and he knew how to decode it (Nasar, 1998, p. 16).

From that day on, there were times Nash was productive, but there were also times when he had disordered thoughts, mumbled to himself without thought of those around him, and experienced delusions of situations that did not exist. He felt there were individuals around him who put him in danger. He even wrote letters to officials in the U.S. government to suggest these individuals were setting up alternative governments. John Nash suffered from schizophrenia.

In Terri Cheney’s memoir Manic (2008), the author, who rose to success as an entertainment attorney in Beverly Hills, told of her experience of exceptional energy. She described one time she was in Santa Fe, New Mexico:

The mania came in four-day spurts. Four days of not eating, not sleeping, barely sitting in one place for more than a few minutes at a time. Four days of constant shopping—and Canyon Road is all about commerce, however artsy its façade.

She further described her experiences:

Mostly, however, I talked to men. Canyon Road has a number of extremely lively, extremely friendly bars and clubs, all of which were in walking distance of my hacienda. It wasn’t hard for a redhead with a ready smile and a feverish glow in her eyes to strike up a conversation and then continue that conversation well into the early-morning hours, his place or mine. (pp. 6–7)

Many individuals experience feelings of high energy or sexuality that would not be considered a mental disorder. However, as you will see in Chapter 6 on mood disorders, those with bipolar disorder often experience high levels of energy for long periods of time and an intense desire to engage in sexual activity, gambling, or shopping. Our task is to understand which types of activities would be considered psychopathology or mental illness.

At one time in our history, health professionals distinguished between physical disorders and mental disorders: Physical disorders involved the body, and mental disorders involved the mind. For example, addiction was at one time seen as a lack of will, with little to do with physiology. Today, we see the close connection of the brain with what were previously considered mental processes. Mental disorders are brain disorders. Further, those physiological processes involved in physical disorders, such as the immune system, the bacteria in your gut, the turning on and off of genes, and the chemical processes of the body, are equally involved in mental disorders.

In this book, the terms psychopathology, mental disorders, or mental illness refer to those disorders traditionally described in scientific and professional research and practice. Psychopathology is the word commonly used in the neurosciences and the one you would want to use when performing literature searches in research and clinical journals. Abnormal psychology as a research area has a long tradition in psychology, and this tradition will be noted by that term. In the middle of the 20th century, a textbook such as this one would have focused more on the description of particular disorders than on scientific research. With the advent of the neurosciences, mental disorders and their relationship to the brain have become an important focus of research. Overall, this was referred to by the term psychopathological research. To reflect the strong scientific tradition currently seen in the study of psychopathology, the name of the Journal of Abnormal Psychology was changed in 2022 to the Journal of Psychopathology and Clinical Science (Patalay & MacDonald, 2022).

Defining Psychopathology and Understanding Its Components

Mental disorders are part of our human condition. We have many names for these conditions. We speak of people with mental illness. For over a century, psychologists have studied these conditions in terms of abnormal psychology, which is the study of abnormal behavior. Others have used the term psychopathology. This is in contrast with pathophysiology, or pathology of our physiology. Slang words such as crazy or nuts have been around for hundreds of years. However, many of these terms stigmatize those who experience a mental disorder. To avoid stigmatizing of groups of people, person-first language, such as “an individual who experiences schizophrenia,” or “a person who experiences depression,” is more widely used today. However, some terms referring to psychopathology have endured in our legal system. For example, one of the oldest legal terms is insanity, or insane, which comes from the Latin meaning “not healthy.”

Mental disorders have been with us throughout our human history. Since the time that written language became a part of our experience, humans have described mental disorders. We find such descriptions in Egyptian, Greek, Chinese, Indian, and other texts throughout world history. Today, our films, novels, plays, and television programs often portray problems experienced by those with mental disorders.

The experiences of the individuals described in the chapter opening give us insights into the nature of mental illness. Terri Cheney told how she experienced great energy, which lasted for 4 days. She described the experience of mental illness as something happening to her. In this sense, Terri Cheney and John Nash did not feel they had an alternative way of acting. Thus, one important characteristic of mental illness is the lack of control over one’s experience. This can also be described as a loss of freedom or an inability to consider alternative ways of thinking, feeling, or doing. Some individuals show this loss mainly in terms of emotional experiences, as in the case of Terri Cheney with bipolar disorder. Others show the loss in terms of cognitive processes, such as the experiences of John Nash. At the beginning of many of the chapters of this book, you will read first-person accounts from individuals with particular disorders. In this way, you can discover how people with a mental disorder experience their world.

Another common theme seen in psychopathology is the loss of genuine personal contact. Individuals with depression or schizophrenia often find it difficult to have social interactions as experienced by other people. Just having a simple conversation or talking to clerks in stores may seem impossible. Mental illness not only affects individuals’ interpersonal relationships but also their relationship with themselves, their intrapersonal relationship. When individuals with schizophrenia or depression talk to themselves, they often think negative thoughts about who they are and what will happen in the future.

In many cases, the experience of a mental disorder results in personal distress. Not being able to get out of bed, or feeling that a voice in your head is telling you that you are evil, or worrying that a rice cake or an apple will make you fat all represent different degrees of distress.

Thus, we can consider four important personal components in psychopathology (Table 1.1). These are a loss of freedom or ability to consider alternatives, a loss of genuine personal contact, a loss of connection with one’s self and the ability to live in a productive manner, and personal distress. As you will see with the disorders presented in this book, personal distress over time is one of the criteria required for a diagnosis to be made. There is also a global component in which the person’s behavior and experiences are considered to be deviant in terms of cultural and statistical norms.

Table 1.1 Four Key Personal Components of Psychopathology

1. Loss of freedom and ability to consider alternatives

2. Loss of genuine personal contact

3. Loss of connection with one’s self and the ability to live in a productive manner

4. Personal distress

Impact of Mental Disorders

Today, the National Institute of Mental Health (NIMH) estimates that 22.8% of the U.S. population experiences a mental disorder during a given year (see For Further Reading at the end of this chapter). This represents roughly 57.8 million people in the United States (Figure 1.1).

Having a mental disorder results in lost productivity, lost personal enjoyment, and potentially even premature death. The World Health Organization (WHO) estimated that in the United States and Canada, mental disorders cause a greater loss in what they refer to as disability-adjusted life years (DALYs) than cardiovascular disease or cancer. DALYs represent the total number of years lost due to illness, disability, or premature death (see For Further Reading).

With mental illness being so common, you might think that we as humans would have a complete understanding of the factors involved. However, this is not the case. We are not even sure how to refer to individuals with mental disorders. Are they abnormal? How you answer this question may be related to your experiences, including your cultural perspective.

Depending on your perspective, one can be normal or abnormal. Many famous artists such as the Impressionists of the 19th century had their work initially rejected because it did not fit into the standards of what was considered “good art” at the time. However, today we appreciate that these artists showed us another way of viewing the world. Likewise, many movies and online media today would be rejected at a previous time as not representing mainstream values. Being part of the LGBTQ community was considered a mental disorder at one time. Further, what would be acceptable in one culture might be seen as completely “crazy” in another.

Stigma and Mental Disorders

As you will see throughout this book, experiencing a mental illness does not mean that one has to live a limited life. Individuals like John Nash and Terri Cheney not only have had productive careers, but they also have enjoyed successful personal relationships. However, many children, adolescents, and young adults with a mental illness report being told they could never perform in a high-level profession or have the types of relationships that others have. Mental disorders are seen throughout the U.S. population regardless of gender, age, and race/ethnicity (see Figure 1.1).

There is often a stigma experienced by those with a mental disorder. Historically, stigma has been defined as a mark of disgrace associated with a particular person. In psychological terms, stigma involves negative attitudes and beliefs that cause the general public to avoid certain people, including those with mental illness. Throughout the world, those with mental illness experience stigma. In many cultures, they are seen as different. When they are thus stigmatized, they are no longer treated as individual people, but only as part of a group who is different. It becomes an “us versus them” way of thinking.

Part of the stigma comes from inaccurate information about those with mental illness. For example, many people think that anyone with a mental illness is violent. In 2012, a mass shooting killed 20 children and 6 teachers at the Sandy Hook Elementary School in Newtown, Connecticut. Immediately after, it was suggested that the killer had a mental illness. Officials of the National Rifle Association claimed that this crime could not have been committed by a sane person. However, the data do not support a strong relationship between mental disorders and violence.

The MacArthur Foundation followed hospitalized individuals with mental illness after their release and found that only 2% to 3% became involved with violence with a gun. As a general rule, individuals with mental illness do not show more violent tendencies than is seen in the general population. However, particular disorders such as antisocial personality disorder (psychopathy) are associated with serial killers and other violent criminals. Also, substance abuse can increase violence in some individuals. With these exceptions, however, having a mental illness has not been found to increase violence toward others.

Stigma can be seen on a number of levels. If a society believes that mental illness is the fault of the person, and that individuals can change themselves by willpower, then it is less likely to spend the money necessary to set up clinics and train professionals. For similar reasons, society may also be less likely to set up school-based programs to help adolescents contend with bullying or handle thoughts of self-harm or suicide. As well, companies may not be willing to include mental health treatment in their insurance coverage, or they may place limits on benefits for treatment of these disorders.

As a society, Americans demonstrate a number of different values when considering those with mental illness. On the one hand, we may want to help those who experience distress. On the other hand, we may feel it is the responsibility of these individuals to take care of themselves. LENS: American Attitudes Toward Mental Illness portrays some of these differing values.

In the United States, attitudes are moving toward less stigma. In 1996, for example, 54% of the U.S. population viewed depression as related to neurobiological causes. During the following 10 years, this increased to 67%. With a better understanding of the disorders presented throughout this book, it is possible to have a more compassionate as well as intellectual understanding of those with mental disorders.

In this book, three major themes will be explored. The first theme takes a behavioral and experiential perspective on psychopathology. Here, current ways of classifying and describing abnormal behavior are discussed. You will also consider the experience of having a psychological disorder, and this book will present first-person reports from individuals with particular disorders. It is also important to examine the role of one’s social groups and culture.

We will also discuss symptoms and signs. Traditionally, symptoms, such as feeling sad, are seen as subjective, and may be reported by the individual to a professional, whereas signs, such as having a fever, are objective processes that can be measured and would be apparent to a professional. An important aspect of this perspective is the degree to which the symptoms and signs of a particular disorder are seen in a similar manner throughout the world. The universality of mental disorders has been an important consideration for scientists. It is also important to note the role culture plays in the manifestations of behaviors and experiences related to psychopathology.

The second theme examines what we know about particular psychopathological experience from a neuroscience perspective. In particular, the structure and function of the brain as it relates to psychopathology is discussed. With neuroscience techniques such as brain imaging, it is becoming clear that mental disorders are also brain disorders. In fact, with every disorder we will consider in this book, it is possible to examine how the structure and function of the brain is changed. The neuroscience perspective will also help us to consider how certain disorders share a similarity in underlying brain processes. For example, knowing that the same brain networks involved in physical pain are also involved in social rejection helps us understand the experience of each and how they are similar.

The third theme asks much broader scientific questions and examines psychological disorders from an evolutionary perspective. In adopting this perspective, we can think about how certain ways of seeing or being in the world might be adaptive. Being afraid of heights, for example, keeps us from taking unnecessary risks. We can ask if there is any advantage to behaving and feeling in certain ways that others consider abnormal. We can also ask if the disordered behavior is secondary to another process that is beneficial. This could include an attempt by our body to protect itself.

In the same way that we know that having a fever is protective and beneficial to recovering from sickness, we can look for similarities in psychological disorders. We can also ask questions about why particular disorders continue to exist. Individuals with schizophrenia, for example, generally have fewer children than those without the disorder. Thus, you might expect that schizophrenia would have gradually disappeared over our evolutionary history through the production of fewer children with the genetics related to the disorder. However, this is not the case, and in fact, schizophrenia occurs in approximately the same percentage (1% of the population) throughout the world in both developed and developing countries. As will be discussed in more detail later in this book, this suggests that schizophrenia is an old disorder that has existed since humans migrated out of Africa around 100,000 years ago (Benton et al., 2021), and it is not related to stresses unique to developed countries. It also suggests that the multiple genes associated with schizophrenia may be associated with more positive human traits such as creativity.

Levels of Analysis

As we explore together the themes of behavior and experience, neuroscience contributions, and evolutionary perspectives as they relate to psychopathology, you will see that we will move across a variety of levels of analysis ranging from culture to genetics. You can group these levels into three domains. The highest-level domain examines the individual in relationship with others. This includes our culture and society as well as our social relationships. From there, we can look at an individual domain, which includes our actions and our experiences. This is typically how we experience ourselves every day. Included in this are our sensory, motor, emotional, and cognitive processes. We can examine both of these levels as they influence our behavior and experience.

The final domain focuses on the physiological processes that make up our central and peripheral nervous systems. This will take us to the cortical network level, and you will see how neurons and their connections form the basis of information transfer and processing. The most basic level you will be introduced to in this book is the genetic level, which in turn will require us to understand how environmental conditions influence genetic processes. You will also learn about a related process, epigenetics, in which genes can be turned on or off by the environment, and these mechanisms can be passed on to future generations without actually changing the basic genetic structure.

As you will read throughout this book, since the 1970s researchers have come a long way in understanding how various levels ranging from genetics to culture interact with each other in a complex manner. In the next section of this chapter, we will turn to a consideration of culture through the ages that will take us to an understanding of behavior and experience on a number of levels. In later chapters, you will be introduced to additional levels of analysis.

To help focus their work, scientists often concentrate primarily on one of these levels of analysis. However, in this book a more integrative approach that draws on a number of these levels will be used. You should not take any one of these levels of analysis as being more important or truer than another. A similar plea was made by George Engel in 1977 when he helped to develop the biopsychosocial approach to understanding mental illness.

Biopsychosocial Approach

In his 1977 paper in the journal Science, George Engel introduced the term biopsychosocial. He suggested that individuals with mental illness or another medical disorder should be understood from more than just a biological perspective. Type 2 diabetes, for example, is a disorder, but it is also related to how the person eats and exercises. Likewise, depression and anxiety can be influenced by social and emotional factors. Thus, it is necessary to see the signs and symptoms of the disorder in a larger context. Otherwise, one has a limited perspective that ignores the social, psychological, and behavioral dimensions of any disorder. Therefore, as a mental health professional, you would want to know more about an individual than just the symptoms that the person describes, as represented in Figure 1.2. This could be their family life, work conditions, and cultural practices as well as eating habits and how the person exercises.

Considering psychopathology from evolutionary and cultural perspectives goes beyond the traditional psychological and physiological considerations (Ray, 2013). These perspectives make us realize that for at least the last 100,000 years, humans have been social beings who have lived within the context of a group in which there were interactions related to gathering and preparing food, having sexual relations, and being part of a community. Cultures developed from this.

The cultural perspective emphasizes the social world in which a person lives (Krendl & Pescosolido, 2020; López & Guarnaccia, 2000). In this sense, culture can be viewed as “information capable of affecting individuals’ behavior that they acquire from other members of their species through teaching, imitation, and other forms of social transmission” (Richerson & Boyd, 2005, p. 5). From this perspective, culture can be seen as a system of inheritance. Humans learn a variety of things from others in their culture, including skills, values, beliefs, and attitudes. Historically, parents and others taught children how to perform particular tasks such as farming, toolmaking, and hunting. In addition, human culture has formalized learning in the form of schools and apprenticeships. Cultures also differ in their level of economic development and the amount of resources they devote to mental health. In Cultural LENS: Global Mental Health: Available Treatment, the availability of mental health professionals across the world is described.

For a more complete understanding of psychopathology, it is important to understand the particular rules a culture has for expressing both internal experiences and external behaviors (Marsella & Yamada, 2000). One simple way to distinguish cultures is whether they emphasize the importance of individual achievement, such as those cultures seen in the United States and Europe, or whether they emphasize collective values and working together, as seen in Asian cultures, such as those of China and Japan. This in turn can influence the type of psychological distress experienced. For example, social anxiety is more common in collective as compared to individualistic cultures (Hong, 2018). What may be a common stress-free experience in one culture may lead to stress and anxiety in another. Even what individuals tell themselves about having a mental disorder can vary from culture to culture. Likewise, artistic and spiritual experiences considered normal in one society may be considered “crazy” in another.

Historically, a simplistic view of culture has emphasized how each culture is locally determined, without reference to universal psychological processes. When universal ways of behaving, feeling, or thinking are suggested, this view assumes that this information is acquired by social learning. Although this is an important aspect of culture, such an emphasis will quickly lead you into the outdated nature–nurture debate, which lacks the insights of modern evolutionary and neuroscience perspectives. For example, consider the question of why foods with milk are found in European diets and not in Asian diets. One answer could be cultural preferences. However, a more complete answer includes the fact that Northern Europeans have a gene that allows them to continue digesting milk products after the traditional time of weaning.

This gene would have conferred an advantage to those who carried it since dairy products are a high-quality food source, and over time—probably less than 10,000 years—that advantage would have allowed these genes to be passed on to almost all of the European population. Today, 98% of all individuals in Sweden have this gene. In the United States, with its large European migration, 88% of white Americans are lactose tolerant, meaning they can digest milk products. Native Americans, on the other hand, are lactose intolerant. Overall, this suggests a close connection between cultural and evolutionary perspectives.

The picture becomes even more complicated in terms of psychological processes. There is a particular form of a gene (5-HTT) related to the neurotransmitter serotonin that is associated with being prone to developing higher levels of anxiety and depression. When its occurrence is examined cross-culturally, studies have shown that 70% to 80% of Japanese individuals carry this gene, whereas only 40% to 45% of Europeans carry it (see Ambady & Bharucha, 2009). Likewise, brain imaging studies have shown that cultural values can influence which areas of the brain are active during self-evaluation (Chiao, 2011; Knyazev et al., 2021).

The larger question raised by these studies is whether this genetic variation influences the manner in which cultural structures formalize social interactions and how this might be related to what is considered mental illness. That is, a society that has more individuals who are prone to anxiety may develop different forms of social interaction than one that does not. Not only can the environment influence genetics, but genetics can also influence culture. This work is just beginning to be applied to viewing psychopathology from a cultural standpoint.

Considering how a condition such as lactose tolerance is found in some groups of individuals around the world and not in others gives us additional insights into when this condition may have developed. Since lactose tolerance is not found throughout the world but is limited to particular groups, one would assume that it was not part of the human condition when humans migrated out of Africa some 100,000 years ago. We can ask similar questions in terms of psychopathology. One question might be how long, in terms of our human history, a particular psychopathology has existed.

Let’s take schizophrenia as an example. A WHO study examined the presence of schizophrenia in a number of countries with very different racial and cultural backgrounds (Sartorius et al., 1986). If schizophrenia had an important environmental component, then you would expect to see different manifestations of the disorder in different cultures. Higher-income countries would show different rates from those of lower-income countries. Areas with different climates might also show differences, as is the case with multiple sclerosis. What these authors found was that, despite the different cultural and racial backgrounds surveyed, the experience of schizophrenia was remarkably similar across countries. Likewise, the risk of developing schizophrenia was similar in terms of total population presence—about 1%. Further, the disorder had a similar time course in its occurrence, with its characteristics first being seen in young adults.

The evolutionary and cultural perspectives help us ask questions such as what function a disorder might serve, as well as how it came about. For example, humans fear animals they have little contact with but do not fear more likely causes of danger such as automobile accidents. Unlike other species, humans live in environments that are different in many respects from those that shaped our early evolutionary history. We have developed large cities and the technological abilities to communicate instantly around the planet. We have also developed ways to mitigate conditions such as the weather experienced in our personal environment that would have played a greater role in our lives thousands of years ago. Compared with other species, humans live less in nature and more in culture. However, it is important in considering psychopathology to remember the environment in which humans as a species developed.

In thinking about our evolutionary history, we can consider how one basic human process developed in relation to an earlier one. For example, in the same way that pain can be seen as a warning system to the body to protect it from tissue damage, anxiety may have evolved to protect the individual from other types of potential threats. In fact, an evolutionary perspective has led to neuroscience research findings that social processes such as feeling rejected use similar brain circuits as those processes involved in physical pain. Further, many of the outward expressions of social anxiety parallel what is seen in dominance interactions in primates. Submissive monkeys avoid contact with more dominant ones, just as humans experiencing social anxiety avoid more dominant individuals. Thus, one hypothesis would be that anxiety may have its evolutionary origins in dominance structures. If this were true, we might expect to see some relationship to sexual instinctual processes, as is the case with dominance. Indeed, social anxiety begins to show just prior to the onset of puberty—around 8 years of age. Of course, this merely shows how evolution may be related to anxiety. The evolutionary perspective can help us think about the roots of psychopathology as well, and it will be a recurring theme of this text.

Is Psychopathology Universal?

If psychopathology is part of our human makeup, then we would expect to see similar manifestations of it worldwide. One classic study was performed by Jane Murphy (1976) of Harvard University. It dates from the 1970s when mental illness was considered to be related to learning and the social construction of norms. In fact, some suggested that mental illness was just a myth developed by Western societies. In this perspective, neither the individual nor their acts are abnormal in an objective sense. One important implication of this view was that what would be seen as mental illness in a Western industrial culture might be very different from what was seen as mental illness in a less developed rural culture. That is to say, mental illness in this perspective was viewed as a social construction of the society. The alternative to this perspective is more similar to other human processes such as emotionality, in which humans throughout the world recognize similar expressions of the basic emotions. If mental illness is part of our human history, as evolutionary psychologists suggest, then we would expect to find similar manifestations across a variety of cultures.

Murphy first studied two geographically separate and distinct non-Western groups: the Inuit of northwest Alaska and the Yoruba of rural tropical Nigeria. Although many researchers of that time would have expected to find the conceptions of normality and abnormality to be very different in the two cultures, this is not what Murphy found. She found that these cultures were well acquainted with disturbed thought and behavior processes in which a person was said to be “out of his or her mind.” This included the person doing strange things as well as hearing voices. Murphy concluded that processes of disturbed thought and behavior similar to schizophrenia are found in most cultures and that most cultures have a distinct name in their language for these processes.

In addition, Murphy reported that these cultures had a variety of words for what traditionally is referred to as neurosis, although today we would call it anxiety or depression. Mood disorders include feeling anxious, tense, and fearful of being with others as well as being troubled and not able to sleep. One Inuit term was translated as “worrying too much until it makes the person sick.” Thus, it appears that most cultures have a word for what has been called neurosis, what has been called psychosis, and what has been called normalcy. What is also interesting is that many cultures also have words for people who are “out of their mind” but not “crazy”: witch doctors, shamans, and artists.

To add evidence to her argument that psychopathology is indeed part of our human nature, Murphy also reviewed a large variety of studies conducted by others that looked at how common mental illness was in different cultures. The implication here is that if its prevalence is similar in cultures across the world, then it is more likely to be part of the human condition rather than culturally derived. What these studies suggest is that many forms of mental illness such as schizophrenia are found at similar rates around the world. Overall, this research established that mental illness was not a created concept by a given culture, but rather part of the human condition in both its recognition and its prevalence. However, one’s culture plays a role in how mental illness is manifested in a specific society.

Humans have gone from a worldview in which magic, including the idea that you could be possessed by spirits or demons, produced mental illness to a time in which our scientific understanding describes a complex set of processes on many levels that contribute to mental illness. As you have seen, these levels go from society and culture to research from the neurosciences, including the role of genes and neurons.

Today, we see those with mental illness as whole people with both abilities and deficits. In terms of the future, there is a growing movement to empower people with mental disorders to have a greater say in their treatment. A person’s high functioning and ability to make decisions are not completely taken away by having a mental disorder. The person is still able to describe their experiences and, in the best of conditions, to ask others for help. However, this is getting ahead of ourselves.

Psychology seeks to describe and understand human behavior and experience. In fact, as humans, we have a long history of trying to understand ourselves. In this section, you will see some of the historical conceptions that have influenced psychology (see Finger, 2000, or the classic Boring, 1950, for more information). One of these conceptions is the role of the body and its involvement in our mental processes. Some of the ideas we will examine date back thousands of years yet still influence our views today.

Ancient Greek and Roman Influences—Mental Illness Involves the Brain

Beginning with Pythagoras in the 6th century BCE, whom we know for his theorem concerning the sides of a right triangle, there was an emphasis on identifying the underlying scientific principles that may account for all forms of behavior. Pythagoras not only coined the term philosophy, which can be translated as love of meaning or wisdom, but also began to set the stage for understanding human behavior and experience as related to internal processes and natural causes. This was in contrast to the prevailing view that human behavior and related disorders reflected the actions of the gods, such as the belief that mental illness was a divine punishment. Pythagoras was one of the first to see the brain as the structure involved in human intellect as well as in mental disorders.

In the next century, Hippocrates, often seen as the father of modern medicine, moved this concept to the next level with his emphasis on careful observation and a continued articulation of the idea that all disorders, both mental and physical, should be sought within the patient. His view of the brain suggests it is the brain that produces “joys, delights, laughter and sports, and sorrows, griefs, despondency, and lamentations.” He further notes that “we become mad and delirious, and fears and terrors assail us, some by night, and some by day, and dreams and untimely wanderings, and cares that are not suitable, and ignorance of present circumstances, desuetude, and unskillfulness. All these things we endure from the brain” (Hippocrates, 400 BCE/n.d.).

Galen (130–200 CE) was a physician in the Roman Empire who influenced Western and Islamic thought until the Renaissance. Some see him as a representation of the beginning of experimentation in medicine because he used dissection to better describe the structure and function of physiological structures. His work as a physician to the gladiators would have also given him firsthand knowledge of the consequences of trauma and its treatment.

During his lifetime, Galen wrote hundreds of treatises on science, medicine, and philosophy. He was largely a champion of empiricism, which stresses the use of direct observation as a means of gaining information. Writing in his treatise On Medical Experience, Galen (ca. 165–175 CE/1944) stated, “I am a man who attends only to what can be perceived by the senses.”

From chance encounters with human accidents and trauma and his anatomical work using a variety of animals, Galen carefully described the brain; the cranial nerves that are involved in sight, smell, movement, and other functions; and the nerves of the sympathetic nervous system involved in fight-or-flight reactions, among others. From his experiments with animals, Galen knew that blood was transported throughout the body. He had an early theory of how blood was changed by the organs based on the idea of spirits. Galen believed that blood was made in the liver, which gave it natural spirits. It then went to the heart where it developed vital spirits and then, with the introduction of air to the blood on the way to the brain, it was transformed into animal spirits. These animal spirits could be stored in the ventricles of the brain until they were needed. Today, we think in terms of hormones rather than spirits. Galen’s works became the encyclopedia of medicine for the next 1,500 years.

Psychopathology in the Middle Ages

Although the Greek and Roman periods included individuals who attempted to understand psychopathology in a more humane way, this perspective disappeared as these civilizations declined. During the Middle Ages in Europe, disease and especially mental illness was seen from a religious perspective, with the devil being a major player. That is, when someone was observed to act in strange and bizarre ways, it was assumed that the person was a witch or possessed by the devil. As such, mental illness did not exist. What existed was the devil working through individuals. This view continued in Europe until the 1800s, especially among people with less education.

One of the classic books in this genre was the Malleus Maleficarum (The Hammer of the Witches), published in the 1480s. This book was written by two German priests and approved by the pope. It went through a number of editions and became the handbook of the Inquisition. It explained how witches existed and flew through the air as well as how they should be tortured if they did not confess. In a “catch-22,” the captured witches were tied to a device and lowered into cold water. If they floated, they were thought to be possessed by the devil and most likely were then killed by hanging or fire. If they sank to the bottom and drowned, then they were innocent. During the interrogations, witches were not to be left alone or given clothes, since the devil would visit them or hide in their clothing. Although the writers of the time did not understand the nature of psychopathology, they did describe in some detail particular characteristics of different disorders including bipolar disorder, depression, and such psychotic processes as hallucinations and delusions.

From the Renaissance to the 1700s—The Beginning of Modern Science

Between the time of Galen and the Renaissance, Western science and medicine remained fairly stagnant, with little new knowledge being added. One problem during this period was that authority, which was often the Church, determined what was true or not. Since authority was able to use its own standard of truth, it was difficult to argue another position. For example, the Church was able to say that the earth was the center of the universe, and that was that.

Beginning in the 14th century, however, a new spirit began to emerge in Europe. It influenced art, literature, politics, and science. In art, there was a desire for a sense of realism, which led artists such as Leonardo da Vinci to carefully study the human body. He performed dissections on animals and human cadavers to carefully reveal the structure of organs. Figure 1.5 shows one of da Vinci’s drawings.

With the detailed drawings of human anatomy created by da Vinci and other artists of the time, there was now the possibility for the scientists of the 1600s to consider function. One important focus was the manner in which the nervous system allows us to perform both involuntary and voluntary functions. How physiological processes are involved in remembering, moving, feeling, and thinking became topics of consideration. Mechanical models emerged, as illustrated by the writings of French philosopher René Descartes (1596–1650).

Descartes was intrigued by mechanical machines such as the large clocks in Europe with moving figures or water displays in large fountains. By analogy, he assumed that reflexes or involuntary actions of organisms were based on similar principles. Thus, moving your hand quickly from a hot stove or even digesting food was seen as a mechanical operation. For Descartes, all animal behavior could be explained by mechanical principles, as could human involuntary actions. In Figure 1.6 from Descartes’ work, you can see the mechanical means by which a hot fire would cause an involuntary or reflexive movement.

The important distinction that continues today is that behavior can be categorized as either involuntary or voluntary. Voluntary actions such as thinking or consciously performing an act were different in that they required a mind, and humans were the only organism to have a mind, according to Descartes. By thinking, humans can know with certainty that they exist—thus, the famous philosophical statement of Descartes, “I think, therefore I am.”

Given his understanding that the bodies of animals are totally mechanical and that humans have both a body and a mind, Descartes created a mind–body distinction that science has had to face in its explanations. The problem is, how can a material body including the brain be influenced by an immaterial process such as the mind? How can a thought influence a cell in the brain?

Although today we generally talk about the mind–body problem, the metaphysics of Descartes’ era would often make the distinction between body and soul. Descartes answered this problem by suggesting that the rational soul was able to control the mechanical body by having both functions come together in one particular organ of the brain, the pineal gland. It is in the pineal gland, Descartes claimed, that the mind not only controls the body but also senses the nature and flow of the mechanical nervous system.

Today, most neuroscientists see the mind as resulting directly from the brain and believe that the mind–body problem is not actually a problem to be solved. However, the question of whether particular behaviors seen in individuals with mental illness represent involuntary processes performed without the benefit of a conscious mind has plagued our legal understanding of mental illness.

In the 1600s, science as a way of knowing about the world began to emerge. At the beginning of this period, prior authorities such as Aristotle or the Church determined the worldview. In this century, Galileo led a movement that would eventually replace authority with experimentation. This movement toward experimentation was greatly aided by Galileo’s own inventions, such as the telescope, the thermometer, an improved microscope, and a pendulum-type timing device. Each of these instruments allowed people to experiment and answer for themselves the questions of nature. With Galileo’s work, a new science based on observation and experimentation was beginning. Galileo was part of a revolution that was to challenge authority. In the 1680s, Isaac Newton’s classic work Principia was published (Newton, 1687/1969). Designated by science historian Gerald Holton (1952) as “probably the greatest single book in the history of science,” this work describes Newton’s theories of time, space, and motion as well as his rules of reasoning for science.

The developing spirit of science during the 1600s set the stage for a new breed of scientist to emerge. One of these scientists was an English doctor, Thomas Willis (1621–1675). He was interested in neurology and in fact coined that term along with a number of anatomical terms, such as lobe, hemisphere, and corpus striatum. He may also have been the first person to use the word psychology in English.

Willis sought to combine the study of brain structure and function. He suggested that lower-brain structures were responsible for more basic functions of life and that these structures could be found across a variety of vertebrates. On the other hand, those structures located higher in the brain must be involved in more advanced processes seen in higher organisms such as humans. Implicit in this idea is a break with Descartes’ suggestion that animals are only machines.

By the end of the 1700s, the nervous system had been completely dissected and the major parts described in detail. The brain was seen to be composed of gray matter and white matter, terms we continue to use today (Figure 1.7). White matter was involved in moving information to and from the gray matter. Today, we have a fuller understanding of brain structure, with the thin outer shell of the brain consisting of cells, which appear to be a darker color and are thus called gray matter. Underlying this are the axons, which transfer information throughout the brain. Their myelin sheaths are lighter in color, and thus these areas are referred to as white matter. Myelin is made up of fats and proteins and wraps around axons like insulation does around electrical cables, resulting in an increased speed of information transmissions.

Also by the 1700s, scientists knew that there was a general pattern in all human brains in how the brain was structured in terms of surface structures or bumps, which were called gyri, and the grooves between them, referred to then and now as sulci and fissures. The present-day terms used to describe parts of the brain also come from Latin, so the lobes of the brain are the frontal lobe, parietal lobe, temporal lobe, and occipital lobe. This can be seen in Figure 1.8.

Scientists of the 1700s also determined that the nervous system had a central division consisting of the brain and spinal cord and a peripheral division consisting of nerves throughout the body (Figure 1.9).

The 1700s to the 1900s

With the basic structure of the nervous system known, scientists of the 1700s began a quest to understand how the system developed and how it worked. One of the contributions of this quest was the realization that the body created and used electrical activity in its basic processes. Today, this electrical activity shows differences in various types of mental illness.

Scientists such as Luigi Galvani and Emil du Bois-Reymond were able to show that electrical stimulation causes a frog’s leg to twitch. With this demonstration, nerves began to be thought of as wires through which electricity passes. Further, it was determined that the brain could itself produce electrical activity. The greater impact of this discovery was that electricity was also something that could be measured, thus setting the stage for the following centuries in which experimentation in the electrical activity of the brain and body would play a significant role in physiology and psychology.

One discovery during the early part of the 1800s was that there is a system for sending information to the muscle, which results in muscle movement, and another system for bringing sensory information back to the brain. When you hold a glass, for example, the sensory or affector system relays information on what the object you are touching feels like, whereas the muscular or effector system tells the muscles how to hold and pick up the glass. Thus, in many nerves there are connections for both receiving and sending information (Figure 1.9). These pathways are called fiber tracts.

At the level of the spinal cord, these fiber tracts split, with the sensory information being conveyed by the dorsal root and the action or motor information involving the ventral root. By the 1850s, Hermann von Helmholtz had measured the speed of the nerve impulse and found it to be around 90 feet a second, which is a little more than a mile a minute. This is much slower than the speed of electricity in a copper wire, which approximates the speed of light (186,000 miles per second). However, the advantage of the nerve impulse—as shown in later research—is that it is not diminished over the length of its travels.

One important realization of the 1700s was that particular functions could be localized to different parts of the brain. One person often cited today is Joseph Gall. Although Gall was correct in suggesting that the frontal part of the brain involved higher cognitive processes and social determinations, he was wrong in assuming that somehow brain function would be reflected in the shape of (and bumps on) the skull. If an individual were good at a particular ability, Gall assumed that their skull would look different from another person’s skull who was not as talented. To support this idea, he examined the skulls of people at the extremes, such as great writers, statesmen, and mathematicians, as well as criminals, people with mental illness, and individuals with particular pathologies. Overall, he defined 19 processes that he thought humans and animals both performed and another 8 that were unique to humans (Figure 1.10).

Gall and his followers never scientifically tested their ideas, and research by others did not support their claims about the structure of the head. What Gall did that was supported was to suggest viewing the brain as capable of performing a variety of functions and that these functions could be localized in different parts of the brain.

Abilities related to understanding and producing language greatly aided specific discoveries related to cerebral localization of function. Physicians began to collect considerable information on patients who had a variety of difficulties with language. Some patients could understand language but could not produce speech. Others had trouble remembering words. Still others could not understand language.

In 1861, a major turning point occurred when physician Paul Broca examined a patient who could understand language but could not speak. This patient was sent to Broca because of a much more serious medical condition and died shortly thereafter. Broca then performed an autopsy and reported an abnormality in an area on the left side of the frontal lobe. Based on a variety of cases, Broca was able to show that language is a left hemispheric process and that damage to the frontal areas of the left hemisphere results in problems in higher executive functions such as judgment, the ability to reflect on a situation, and the ability to understand things in an abstract manner (Finger, 2000). Today, the area related to language production in the left hemisphere is called Broca’s area (Figure 1.11).

In 1874, Carl Wernicke published a paper that suggested that language understanding was related to the left temporal lobe. He studied patients who were unable to comprehend what they heard. At the same time, they were able to produce fluent speech, although it was incomprehensible and included nonexistent words. The specific place in the brain identified by Wernicke is now called Wernicke’s area (see Figure 1.11). The discoveries of Broca and Wernicke helped the scientific community understand that language was made up of different processes, including the ability to understand and to produce language.

Throughout his career, British neurologist John Hughlings Jackson examined the brain from a developmental and evolutionary perspective (see Williamson & Allman, 2011). Hughlings Jackson saw the brain as composed of three levels. The earliest part of the brain to evolve was the spinal cord and brain stem, which controlled the vegetative functions such as breathing, sleep, and temperature control. The next level to evolve included the basal ganglia, which is connected to various other parts of the brain and is involved in movement. The third level to evolve included areas involved in higher cortical functions, including thought. It is the task of the higher level to keep the person aware of changes in the environment.

Within this framework, Hughlings Jackson suggested principles based partly on evolutionary analysis. One important principle is hierarchical integration through inhibitory control. By this, he meant that the various levels of the brain, such as the brain stem, the limbic system, and the neocortex, are able to interact with each other. Further, the type of interaction from the higher levels restricts or inhibits the lower levels.

In terms of mental illness, Hughlings Jackson (1894) suggested that symptoms such as illusions, hallucinations, and delusions are not in themselves the result of disease. Rather, it is when higher-level processes no longer inhibit the earlier evolved processes of the brain that these symptoms appear. Hughlings Jackson referred to this process as dissolutions. Dissolutions are the reversal of the normal process of evolution. Thus, the primitive experiences seen in psychosis, for example, represent the primitive parts of the brain working normally. What is missing is the relationship of these primitive areas with higher mental processes.

A Growing Understanding of the Role of Evolution

Another big idea that emerged in the 1800s was that all of nature is in constant flow and that things, including organisms, change. This idea focused on the evolution of species and is most often associated with the work of Charles Darwin (1809–1882). Variation was to become one of the major components of Darwin’s thinking concerning evolution. In fact, he began his thinking with the assumption that heritable variations can and do occur in nature. Darwin then presented the important realization that not all plants or animals that come into existence survive. Many organisms such as sea stars, for example, produce millions of eggs of which only a limited number survive. Depending on climate conditions, food supply, predator population, and a host of other factors including disease, only a limited number of those born survive to maturity.

Consequently, Darwin (1859) suggested, “There is a frequently recurring struggle for existence.” Who is to survive in this struggle? Darwin suggested that if an individual has even a slight variation that helps it to compete successfully for survival, then over time the species will be made up more and more of members with these characteristics and less and less of individuals lacking these features. This process is referred to as natural selection. Darwin described this process in his 1859 book, On the Origin of Species by Means of Natural Selection.

Darwin later extended the theory of natural selection to include sexual selection, or the manner in which males and females choose a mate. This work is described in his 1871 book, The Descent of Man. Darwin noted that males and females differ not only in terms of organs of sexual reproduction but also in secondary sexual characteristics such as mammary glands for the nourishment of infants in females or facial hair in males. According to Darwin, sexual selection depends on the success of certain individuals over others of the same sex. Darwin also saw that besides same-sex competition, there is also competition to attract members of the opposite sex. There has been continuous debate and research concerning what attraction means for males and females of all species.

Darwin began the Origin work with the question of natural selection especially as it related to animals. In The Descent of Man, he expanded these ideas to humans and also examined the question of sexual selection. In other works, such as his notebooks, he extended his research to cognitive and emotional processes. The broad question is that of how psychological functions have evolved. One answer he gives is that living in social groups produces an increase in cognitive ability. Darwin also presents notes on memory and habit, imagination, language, aesthetic feelings, emotion, motivation, animal intelligence, psychopathology, and dreaming (Gruber, 1974). One important question is the manner in which self-preservation, sexual selection, and social processes are reflected in psychopathology.

Overall, Darwin helped us understand the close connection between the environment and genetic processes, although Darwin did not know about genes at that time. Today, we know that this close connection makes such questions as what is responsible for our behavior, nature in terms of genes or nurture in terms of experiences, meaningless. As you will see later, genes influence our environment and our environment influences which genes are activated or not. It is this close connection that allows for change. Humans are born less fully developed at birth than many other species and thus are sensitive to changes in their environment as they continue to develop. Unlike animals that live within nature, humans largely live within the backdrop of our culture. Another part of the complexity with humans is our ability to reflect on ourselves and our world. In this way, a layer of thought, including expectation and imagination, is injected between the person and the environment.

A Search for Organization

One of the themes of the sciences of the 1800s was the search for organization. In understanding psychopathology, an important person associated with this search was the Paris physician Jean-Martin Charcot (1825–1893). Charcot sought to bring organization to an understanding of neurological disorders through a variety of methods such as careful observation. This observation was of both what the patient said, which we refer to today as symptoms, as well as what the clinician observed, or what we refer to as signs. The overall search was for which signs and symptoms go together to form a syndrome. An additional technique—autopsy, or examination of the body after death—further allowed for the connection of syndromes with underlying anatomy. Autopsies allowed for the determination of which tissue showed signs of pathology. Using this method, Charcot was able to confirm the correctness of Hughlings Jackson’s thoughts on neurological organization. Overall, Charcot showed that the human motor cortex is organized similarly to that of other animals, with the left hemisphere controlling the right side of the body and vice versa.

Charcot is best known for initially describing brain disorder relationships for a number of motor-related disorders, including Parkinson’s disease and multiple sclerosis. Charcot also established Tourette’s syndrome as a separate disease when he asked his assistant Gilles de la Tourette to help him. De la Tourette wrote of cases that included a teenage boy who would show involuntary movements and scream swear words.

Charcot was also able to show that conversion reactions, in which the person shows outward signs of trouble hearing or seeing, or being unable to experience pain in the hand, were without any underlying pathology. During Charcot’s time, conversion reactions were referred to as “hysteria.” A young Sigmund Freud heard Charcot’s lectures on hysteria, including the observation that psychological trauma could trigger these reactions. This became the initial basis of Freud’s psychoanalytic work.

Charcot helped to integrate symptoms of a disorder with both psychological and brain processes. He also emphasized that, as in the case of hysteria, much of what had been seen as possession by demons could be viewed as resulting from natural causes. Thus, there was no need for faith healers or church rituals to remove evil spirits. This also encouraged society to view an individual with hysteria or another mental affliction as someone with a disorder rather than as an evil person. Much of Charcot’s work took place at the Salpêtrière Hospital for the poor in Paris. These hospitals served as both research centers and places where treatments were developed for mental illness.

In 1330, a convent of the order of St. Mary of Bethlehem became the first institution for people with mental illness in England. The institution eventually received a royal charter and, over the years, the word Bethlehem became Bedlam, and the institution was referred to as “Old Bedlam.” The English word bedlam comes from this institution. Various reports suggested that the inmates were often chained, treated cruelly, and not given proper food or clothing. As depicted in novels of the day, people in the 1700s would go to Bedlam to see the inmates as an outing in much the same way that today we might go to a zoo. In 1814, some 96,000 people visited the asylum.

In the 1800s, there was a campaign in England to change the conditions for the patients, which led to the establishment of the Committee on Madhouses in 1815. This ushered in a period of concern for the patients rather than seeing them as objects of curiosity as in the previous century. Treatment for patients during the 1800s brought new practices, including the therapeutic value of work.

During this period, there was a spirit throughout the world to adopt a “moral treatment of the insane.” Three important individuals in this movement were Benjamin Rush (1745–1813) in the United States, Philippe Pinel (1745–1826) in France, and Vincenzo Chiarugi (1759–1820) in Italy (Gerard, 1997). In the United States, Rush, who had signed the Declaration of Independence, later established a wing at the Pennsylvania Hospital in Philadelphia for the treatment of mental illness. He is often considered the father of American psychiatry and saw mental illness as a problem of the mind. However, he continued to practice bloodletting as the best treatment for mental illness. Rush developed a tranquilizing chair that he believed would change the flow of blood. Professionals tend to view this invention as neither helpful nor hurtful to the patient. He also wrote the first psychiatric textbook published in America.

In France, Pinel sought to change the way that people with mental illness were treated. He believed that mental illness could be studied using the methods of the natural sciences. In 1793, Pinel became the director of the Bicêtre asylum in Paris. As director, he reviewed the commitment papers of the patients, toured the building, and met with each patient individually. The building was in bad shape, and the patients were chained to walls. As Pinel (1806) himself described the institution, “everything presented to me the appearance of chaos and confusion” (pp. 1–2). Pinel petitioned the government and received permission to remove the chains, and he also abandoned the practice of bloodletting.

Pinel began to carefully observe patients and also talk with them. In these discussions, he attempted to create a detailed case history and to better understand the development of the disorder. This led to a classification system he published in 1789, which sorted mental diseases into five categories: melancholia, mania without delirium, mania with delirium, dementia, and idiocy. In 1795, Pinel became the chief physician at the Salpêtrière (which was then a hospice for poor women), where he remained for the rest of his life. Pinel is known as the father of scientific psychiatry.

Vincenzo Chiarugi was not well known outside of Italy until a paper published in the middle of the last century, which brought his name to the attention of Americans (Mora, 1959). Some 8 years earlier than Pinel, Chiarugi began removing chains from his patients. Early in his career, Chiarugi became the director of a large hospital in Florence that included special facilities for people with mental illness. The institution had been established with the passage of a law in 1774 in Italy that allowed these individuals to be hospitalized. As director of the hospital, Chiarugi created guidelines concerning how patients were to be treated. One of his rules specified that patients were to be treated with respect. He also directed that if restraints were required, they should be applied in a manner to protect the patient from sores and be made of leather rather than chains. He also used psychopharmacological agents such as opium for treatment.

In addition to mental health professionals, a number of other individuals promoted the humane care of people with mental illness. William Tuke (1732–1822) was a successful English merchant and a Quaker philanthropist. Some friends had told him of being turned away from an asylum in York, England, when they had tried to visit a fellow Quaker who had been confined there. Within a few days, the patient was reported dead. Tuke visited the asylum and found the conditions deplorable. Having retired, he decided to devote his life to creating alternative places where “the unhappy might find refuge” (Tuke, 1813).

In 1796, near the town of York, Tuke created the Retreat for Persons Afflicted With Disorders of the Mind. This Quaker retreat, as it was called, carried with it the idea that the individuals who were there should be given respect as well as good food and exercise. There were to be no chains or manacles. The model for the retreat was a farm, and the patients performed farm duties as part of their treatment. Others visited to learn of its operation. In 1813, the Quakers of Philadelphia founded the Friends’ Asylum for the Use of Persons Deprived of the Use of Their Reason, which was the first private psychiatric hospital in the United States. Both the retreat in York and the Friends’ Hospital of Philadelphia continue to function today as places for mental health treatment.

Another individual who contributed to the American mental health movement was Dorothea Dix (1802–1887). While teaching women at the East Cambridge House of Correction in Massachusetts, Dix had her eyes opened to the terrible conditions these women faced. Dix also realized that a number of these women had some type of mental illness. She fought against the idea that those with mental illness could not improve or be helped. From this experience, she devoted her life to crusading for the improved treatment of people with mental illness. As part of this crusade, she visited every state east of the Mississippi River and testified before local and national legislatures. It is estimated that her work led to the establishment of some 40 mental hospitals in the United States and Europe.

By the 1950s, a number of hospital facilities existed in the United States for those with mental illness. These were administered by both state governments and private organizations. This changed in the 1950s as described in LENS: Closing Mental Hospitals in America. This was the result of both the development of psychiatric medications and a movement to switch to a more community-centered idea of mental health care.

In light of the history discussed thus far, mental illness has been considered from two perspectives. The first perspective involves spirituality, often invoking the devil or supernatural forces. This was seen in the worldview of many early humans and was also the perspective of the Christian Church, especially in the Middle Ages. Rituals were performed to remove the demon from the person, which rarely benefited the individual. Today, some churches offer forms of exorcism.

The second perspective is that of psychology and physiology in a broad sense. This perspective uses research and the sciences to understand what mechanisms lead to mental disorders. Treatment involves the manipulation of these mechanisms through psychotropic medications and psychotherapy. The discovery of psychotropic medications greatly changed treatment of mental illness around the world. As noted in the previous LENS, these drugs allowed for individuals to live in a more independent manner. Throughout this book, you will learn about the medications used to treat the major mental disorders.

Throughout our history as humans, we have used natural substances to treat illness. Often, treatment was a hit-or-miss procedure as people learned which substances were more effective than others. With the development of better chemical methods in the past hundred years, scientists began to modify the substances and create them as drugs. Today, we refer to these substances, when used to address mental illness, as psychotropic medications. The overall category of psychotropic medications can be broken into categories based on what they were designed to accomplish. These categories include mood stabilizers, antianxiety drugs, antidepressant drugs, and antipsychotic drugs.

During the U.S. Civil War, a textbook by Union Army Surgeon General William Hammond suggested that lithium bromide be used to treat manic patients (see Perlis & Ostacher, 2016). However, it was not until 1949 that the Australian John Cade reported that lithium had a calming effect on animals and humans with mania. As you will see, lithium is still used to treat mania, which we refer to as bipolar disorder today. Drugs that came to be called antidepressants for the treatment of depression, such as monoamine oxidase inhibitors (MAOIs) and the tricyclic antidepressants (TCAs), were discovered through serendipity in the 1950s (Fava & Papakostas, 2016). SSRIs (selective serotonin reuptake inhibitors) such as Prozac were developed later. You will learn about these substances in the chapter on mood disorders. Benzodiazepines such as Valium have been used for the treatment of anxiety for at least 50 years.

One significant event came in 1952 when a French naval surgeon was attempting to find medications to give to reduce stress before an operation (Freudenreich et al., 2016). He discovered that an antihistamine substance called chlorpromazine left individuals feeling indifferent about their operation. Noticing its calming effect, he suggested that this might be useful in the treatment of mental disorders. In particular, it was discovered that chlorpromazine (trade name Thorazine) helped to reduce the symptoms of schizophrenia and initially became an important antipsychotic medication. This, in turn, led to the reduction in the number of patients in mental hospitals (as noted in the previous LENS). Some of the early antipsychotic medications had problematic side effects. Newer drugs used today have fewer of these side effects.

Other treatment approaches seek to influence the individual’s brain by changing the underlying electrical activity. Some of these treatments are considered noninvasive (Camprodon et al., 2016); that is, there is no requirement that electrodes or other devices be placed inside the brain itself. The oldest of these techniques is electroconvulsive therapy (ECT) in which electrical activity is used to disrupt normal brain activity and produce convulsions (Welch, 2016). ECT has improved over the years with a reduction in motor convulsions and a reduction in the number of brain areas affected. It is seen as an effective treatment for those with severe depression that does not respond to other types of medication or psychotherapy. An alternative to ECT, referred to as transcranial magnetic stimulation (TMS), disrupts brain activity using magnetic stimulation to treat mental disorders, including depression.

More invasive treatments require that electrodes be placed in the brain that change the existing brain networks. The technique has been referred to as deep brain stimulation (DBS) and has been used for the treatment of motor disorders such as Parkinson’s disease, as well as obsessive compulsive disorder (OCD) and depression. Stimulating electrodes are placed deep in the brain, and these are connected to a pulse generator that is placed under the person’s skin, typically below the neck. Today’s devices allow health care professionals to adjust the stimulation from wireless devices outside the skin.

The most invasive procedures are surgeries in which different areas of the brain are removed or their connections disrupted. Severe epilepsy, in which a person has numerous seizures and cannot work or function normally, has been treated in this manner. Today, surgical procedures of the brain are limited to very small areas. In fact, gamma rays rather than a knife are used to make the small cuts. Such small cuts in the brain are used with individuals who show no improvement in epilepsy, depression, or anxiety using standard treatments.

Not all of the biological treatments have been successful. In the first half of the 1900s, as a treatment for mental illness, the frontal areas of the brain were disconnected from the rest of the brain. This procedure, called a frontal lobotomy, was used until the 1950s and then discontinued. It left the person with limited emotional and cognitive abilities. Even during its time, there were serious debates as to its ethics and effectiveness.

As you will see throughout this book, biological approaches play an important role in the treatment of mental disorders. Determining effective treatment is not an either/or question of psychological and biological approaches but an attempt to combine treatments that work together in an effective way. For example, research from 2015 shows that the combination of psychotherapy and lower levels of psychotropic medication is very effective for treating schizophrenia (Insel, 2015; Kane et al., 2016). As you will also learn, psychotherapy and biological approaches work through different brain mechanisms and at different levels of the brain. Throughout the chapters of this book, particular biological approaches will be described in terms of each disorder.

The next section will examine psychological factors involved in developing, maintaining, and treating mental disorders. What people learn through interacting with others and with their environment is crucial. In addition, what individuals tell themselves or how they experience significant others in their lives is an important aspect of this perspective.

Before the middle of the 20th century, very little formal research had been performed to see how effective psychological interventions were. This was also true of traditional medical procedures. Beginning in the 1950s and 1960s, a movement started to determine the effectiveness of both medical and psychological treatments in a scientific manner. In medicine, this came to be known as evidence-based medicine. In psychology, the terms empirically based treatments and empirically based principles refer to treatments and their aspects for which there is scientific evidence of effectiveness (Clark, 2018; David et al., 2018). During the 21st century, there has also been a focus on the importance of understanding diversity and cultural competency within the context of evidence-based care (Huey et al., 2014). Treatment effectiveness is now considered worldwide with diverse populations (e.g., Ravitz et al., 2019). Also, researchers have sought to discover any general factors such as empathy and positive regard on the part of the therapist (Elliott et al., 2018; Farber et al., 2018; Norcross & Lambert, 2018). This research suggests that relationship factors are important to successful treatment regardless of the therapeutic approach used.

As researchers and clinicians began to focus more on approaches and principles for which there was scientific evidence that they were effective, there began a movement to develop effective treatments for particular disorders. There has been more willingness to integrate techniques from the three different approaches as well as from other perspectives. For example, in the chapter on personality disorders, you will see that one of the most researched treatments—dialectical behavior therapy (DBT)—is based on techniques from each of the three approaches described in this chapter. This effective treatment uses aspects of cognitive behavioral, dynamic, and humanistic-existential techniques.

Psychodynamic Perspectives on Treatment

The psychodynamic perspective is based on the idea that psychological problems are manifestations of inner mental conflicts and that conscious awareness of those conflicts is key to recovery. Historically, Sigmund Freud laid the foundation for this perspective.

By the beginning of the 20th century, there was an understanding that psychological processes were an important source of information about mental illness. Freud had worked with Charcot in Paris and observed individuals with hysteria. In this disorder, the experience, such as not feeling pain in a limb or difficulty hearing, did not match the underlying physiology. Witnessing this type of disordered behavior led Freud to seek psychological explanations for the cause and treatment of mental disorders.

Sigmund Freud

Freud was initially trained as a zoologist before he completed medical school. The nature of the neuron was just being discovered, and Freud based his early theories on the neuroscience of his day. He was an enthusiastic reader of Darwin and credited his interest in science to an early reading of his work. A number of Freud’s ideas can be seen as coming from Darwin (Ellenberger, 1970; Sulloway, 1979), although Freud emphasized sexual selection over natural selection. According to Freud, the sexual instinct (libido) is the major driving force for human life and interaction. Freud was also influenced by the suggestion of the neurologist Hughlings Jackson that in our brains we find more primitive areas underlying more advanced ones. Thus, it is quite possible for the psyche to be in conflict with itself or at least to have different layers representing different processes.

For Freud, higher cortical processes could inhibit the experience of lower ones, a process that would come to be called repression. Anxiety is the result of society and culture having inconsistent rules for the expression of sexuality and aggression. This anxiety and our inability to acknowledge these instinctual experiences lead to defense mechanisms and neurosis. Freud believed that the brain was basically a blank slate upon which experiences become connected with one another driven by instinctual processes of sexuality and self-preservation. The human psyche for Freud becomes the real-life laboratory in which nature and nurture struggle.

Freud’s concept of treatment was based on the search for ideas and emotions that are in conflict and the manner in which the person has relationships with other people. His specific treatment came to be called psychoanalysis. One basic procedure was free association, in which an individual lay on a couch with the therapist behind them and said whatever came to mind. It was the therapist’s job to help the client connect ideas and feelings that they were not aware of. One thing Freud was searching for was connections within the person’s psyche when external stimulation was reduced. Dreams were also analyzed in this way, since they are produced outside of daily life.

Other aspects of psychoanalysis included examining resistance, or what the client is unwilling to say or experience, and transference, or the manner in which a person imagined how another person thought about or sought a certain kind of relationship with them. Freud has greatly influenced therapies based on insight. Insight therapy, which has been used to treat disorders such as anxiety and depression, is based on the principle of bringing patterns of behavior, feelings, and thoughts into awareness. In order to do this, it is necessary to discuss past patterns and relationships to determine how they are being replayed or are influencing the present.

A number of dynamically orientated therapies have been shown to be effective (Barber et al., 2021; Fonagy, 2015). One empirically supported therapy based on dynamic principles was developed by Hans Strupp and his colleagues. Strupp embodied the dynamic principles in a therapy of a few months’ duration (Strupp & Binder, 1984). The focus of this therapy is the relationship between the client and other individuals in the client’s life. It is assumed that the client’s problems are based on disturbed relationships. The therapeutic relationship between the client and the therapist offers an opportunity to see disturbed relationships in a safe environment. Transference is an important mechanism in which the client tends to see the therapist in terms of significant others in their life. As the client talks with the therapist, they will replay prior conflicts and enact maladaptive patterns.

The role of the therapist in this approach is mainly to listen. As the therapist, you listen to your clients, seeking to understand what they are saying and how they feel as they describe their world. You would note to yourself when they find talking to you difficult or experience distress as they talk about their life. On a larger level, the therapist is looking for themes and patterns that come from their clients’ pasts. In a relaxed, nonjudgmental manner, it is the task of the therapist to help the client understand the patterns and to see how they interfere with living and having rewarding relationships with others. Different versions of dynamic psychotherapy have been shown to be effective for a number of disorders, especially the personality disorders.

Existential-Humanistic Perspectives

The existential-humanistic perspective begins by asking: What is the nature of human existence? This includes both the positive experiences of intimacy and the negative experiences of loss. Historically, two clinicians influenced by Freud—Carl Jung and Karen Horney—helped to set the stage for the existential-humanistic movement in that they emphasized the value of internal experience.

As the existential-humanistic movement grew, a number of themes became critical. The first is an emphasis on human growth and the need for a positive psychology that moves beyond the discussion of stress and neurosis seen in the psychodynamic approaches. A second emphasis is the idea that psychological health is more than just the absence of pathology. Not having a problem is not the same as finding meaning in one’s life. The third theme stresses the importance of considering not only the external world and a person’s relationship to it, but also the internal world. In the humanistic-existential perspective, the internal world of a person and their experiences are valued. Carl Rogers brought the humanistic movement to the forefront by creating client-centered therapy, also referred to as person-centered therapy. Rogers considered psychotherapy to be a releasing of an already existing capacity in a potentially competent individual. In fact, Rogers emphasized the relationship between the therapist and client as a critical key to effective therapy.

There are three key characteristics of the client-centered approach. The first is empathic understanding. As the therapist reflects back what the client says, the client begins to experience their own innermost thoughts and feelings. The second is what Rogers referred to as unconditional positive regard. That is, the therapist accepts what the client says without trying to change the client. For some individuals who have experienced significant others in their lives as critical of them, to be accepted by the therapist is a new experience. The third characteristic is for the therapist to show genuineness and congruence (agreement). In this way, the therapist models what interactions between two real people could be like.

A number of humanistic-experiential–orientated therapies have been shown to be effective (Elliott et al., 2013, 2021). One of these empirically supported therapies based on humanistic principles was developed by Leslie Greenberg and his colleagues. This approach is known as emotion-focused therapy or process-experiential therapy (Greenberg, 2002). In this therapy, emotion is viewed as centrally important in the experience of self. Emotion can be either adaptive or maladaptive. However, in either case, emotion is the crucial element that brings about change. In therapy, clients are helped to identify and explore their emotions. The aim is to both manage and transform emotional experiences.

Emotion-focused therapy can be thought of in three phases (Greenberg & Watson, 2006). The first phase is one of bonding and awareness in which it is the job of the therapist to create a safe environment for emotional experience to take place. Empathy and positive regard are part of the way the client is helped to feel safe. In the early part of therapy, the client is helped not only to experience an emotion but also to put words to it.

The second phase is evocation and exploration. At this point, emotions are evoked and even intensified. The therapist also helps the client to understand how they might be interfering with their own experience of emotion. Such examples of interference would include changing the subject and beginning to talk about the emotion in a cognitive manner as a way to distance oneself from the experience. The third phase is transformation and generation of alternatives. It is at this point that the therapist helps the client construct alternative ways of thinking, feeling, and doing that are more consistent with their real self. Empirical studies have shown that emotion-focused therapy is effective with depression and emotional trauma (Greenberg & Watson, 2006).

Another therapeutic technique that has gained popularity and been empirically shown to be effective is mindfulness (Creswell, 2017; Ong et al., 2020). Mindfulness techniques were originally meditation techniques developed in Theravada Buddhism. These techniques involve an increased, focused, purposeful awareness of the present moment. The idea is to relate to one’s thoughts and experiences in an open, nonjudgmental, and accepting manner (Kabat-Zinn, 1990). The basic technique is for the individual to observe thoughts without reacting to them in the present. This increases sensitivity to important features of the environment and one’s internal reactions, leading to better self-management and awareness as an alternative to ruminating about the past or worrying about the future. This in turn reduces self-criticism.

Nonjudgmental observing allows for a reduction in stress, reduction in reactivity, and more time for interaction with others and the world. Also, feelings of compassion for another person become possible. This broadens attention and alternatives. Meta-analysis performed by Hofmann, Sawyer, Witt, and colleagues (2010) examined 39 studies of mindfulness. They found significant reductions in anxiety and depression following mindfulness techniques. Grossman and his colleagues (Grossman et al., 2004; see also Hofmann et al., 2011) examined 20 studies and found overall positive changes following mindfulness approaches. Empirical evidence using mindfulness techniques has shown positive change with a number of disorders, including anxiety, depression, chronic pain, and stress (Wielgosz et al., 2019). Mindfulness is also a component of DBT, which is an effective treatment for borderline personality disorder.

Overall, the existential-humanistic perspective emphasizes the emotional level. There is also an emphasis on the value of internal processes and the manner in which the exploration and experiencing of these internal processes can lead to changes in behavior and experience.

Behavioral and Cognitive Behavioral Perspectives

The behavioral perspective, as the name implies, has focused on the level of actions and behaviors. Most histories of behaviorism begin with a discussion of Ivan Pavlov, the Russian physiologist who won the Nobel Prize in 1904 for his work on the physiology of digestion. Pavlov noted in his Nobel Prize speech that the sight of tasty food makes the mouth of a hungry man water. However, what became of interest to behavioral psychologists was not the salivary reflex itself but the fact that other objects associated with the presentation of food could also produce salivation. For example, in Pavlov’s work with dogs, it was shown that any sensory process, such as sound, that was paired with the food would produce salivation. After a number of pairings, the sound alone without the food could produce this reflex. This came to be known as classical conditioning.

Classical conditioning occurs when an unconditioned stimulus, such as food, results in an unconditioned response, such as salivation. If this unconditioned stimulus is paired with a neutral stimulus a number of times, then the neutral stimulus will produce the response. After a period of time, the “conditioned stimulus” such as sound, when presented alone, will no longer produce the response. This process is referred to as extinction. Behaviorists saw classical conditioning as one mechanism underlying the development of mental illness.

John Watson is often described as America’s first behaviorist. His work set psychology on the course of emphasizing environmental explanations for behavior and rejecting the theoretical value of internal concepts. This called into question the value of studying such topics as consciousness and other internal processes. Watson set the course of only studying observable behavior with his 1913 paper Psychology as the Behaviorist Views It. Watson suggested that the proper study of psychology was to focus on behavior and not the mind. Further, Watson saw the goal of psychology as identifying environmental conditions that direct behavior. Under no circumstances should the theory make reference to consciousness, mind, or other internal unobservable events. Watson created a psychology based on observable behaviors alone, which helped promote the development of a strong stimulus–response psychology. Watson’s statement emphasizing the role of the environment in development is well known.

Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I’ll guarantee to take any one at random and train him to become any type of specialist I might select—doctor, lawyer, artist, merchant-chief, and yes, even beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors. (Watson, 1924, p. 82)

As the quote implies, Watson assumed that there existed “talents, penchants, tendencies, abilities” that were part of an individual but that these could be overridden by environmental factors. In fact, Watson demonstrated that an 11-month-old infant named Little Albert could be conditioned to fear an animal such as a lab rat that the infant had previously enjoyed playing with (Watson & Rayner, 1920). The procedure (which would be considered unacceptable and unethical today) was to create a loud noise when the infant was observing the animal. A loud noise will produce a startle response. In a classical conditioning manner, the pairing of the aversive noise and the animal led to conditioned fear. Behaviorists used classical conditioning as a mechanism for understanding phobias and other processes seen in mental illness.

B. F. Skinner became the 20th century’s most vocal proponent of behaviorism. Beginning with his 1938 book, The Behavior of Organisms, Skinner played a significant role in experimental psychology until his death in 1990. His experimental procedure was to demonstrate that an animal, generally a laboratory rat or pigeon, could be taught to make specific responses if, after the occurrence of the desired response, the animal was given a reward, generally food. This procedure came to be known as operant conditioning. The basic idea was that behavior could be elicited or shaped if reinforcement followed its occurrence. Consequently, if these behaviors ceased to be rewarded, the occurrence would decrease. Thus, the emphasis was on behaviors and the rewards that follow them as opposed to the environmental stimuli evoking them.

Skinner suggested that freedom, will, dignity, and other concepts referring to the mind or internal states have no explanatory value. Psychologists should only be interested in the relationship between behavior and consequences, according to Skinner. Even processes such as language learning were seen as the result of words being reinforced and learned one at a time. In this manner, any type of complex behavior was seen as the result of learning simple behaviors, which were then chained together. The larger implication was that humans came into the world ready to be influenced by the reinforcement contingencies of the environment to determine their development and actions in the world. Watson and Skinner ushered in an era in psychology that strongly emphasized the environment and largely ignored any discussion of internal processes or mechanisms for understanding life.

In the mid-20th century, a number of psychologists began to see the limitation of strict behaviorism in that it ignored internal processes. Simple demonstrations, such as offering a 6-year-old a candy bar if he would do a particular task, showed that the idea of a reward was enough to motivate behavior. Also, behaviorally oriented psychologists such as Albert Bandura showed that humans would imitate the behaviors of others even without reinforcement. This type of learning was called observational learning, or modeling. One classic set of studies involved children hitting a Bobo doll after seeing cartoon characters being aggressive. In another study, children watched an adult interact with the Bobo doll in an aggressive or nonaggressive manner. Those children who watched the aggressive adult later showed more aggression than those who watched a nonaggressive adult.

Nonclinical areas of research in psychology, such as the study of cognitive processes and social processes, were demonstrating that humans often make quick decisions based on information that is outside of normal awareness. Humans make these decisions without actually realizing there are alternative ways of thinking. Further, evolutionary thinking was showing how humans come into the world with an evolutionary history such that they develop fears of some objects such as snakes or spiders more readily than fears of a toy truck or a flower. Arne Öhman at the Karolinska Institute sought to determine the basis of fear learning and how it relates to psychopathology (see, e.g., Öhman, 1986). Others emphasized the fact that humans talk to themselves and pay attention to their own thoughts, which can influence behavior. All of these developments moved many in the psychology discipline away from Skinner’s more rigid behaviorism.

The cognitive behavioral perspective suggests that dysfunctional thinking is common to all psychological disturbances. By learning in therapy how to understand one’s thinking, it is possible to change the way one thinks as well as one’s emotional state and behaviors. One basic feature of our thinking is that it is automatic. Ideas just pop into our mind, such as “I can’t solve this” or “It is all my fault.” A number of therapies based on cognitive principles along with behavioral interventions have been shown to be effective (Hollon & Beck, 2013; Newman et al., 2021).

Aaron Beck (1967; see also Beck, 2019, for an overview and update) developed a cognitive therapy for depression in the early 1960s. The model is described in terms of a cognitive triad related to depression (Figure 1.13).

The first component of the triad is the individual’s negative view of self. This is when the individual attributes unpleasant experiences to his own mental, physical, and moral defects. When something negative happens, the person says it is his fault. In therapy, the client can become aware of the content of his thinking. The second component is the individual’s tendency to interpret experiences in a negative manner. That is, the person tailors the facts to fit negative conclusions. The basic idea is that thinking influences emotion and behavior. The third component is that the person regards the future in a negative way. He envisions a life of only hardships and anticipates failure in all tasks. In therapy, the basic idea is that the individual can modify his cognitive and behavioral responses. Overall, the therapy is directed at the automatic thoughts in relation to catastrophizing—believing that nothing will work out; personalization—believing that everything relates to you; overgeneralization—believing that one event is how it always is; and dichotomous thinking—believing that things are either good or bad.

In the history of cognitive behavioral therapy (CBT) research, most therapies were directed at treating particular disorders such as anxiety, depression, phobias, and so forth. However, it was noted that negative affect is present in a number of different disorders (Barlow, Allen, & Choate, 2016). This led to the development of a treatment approach directed at the common underlying mechanisms of these different disorders. Overall, the approach seeks to help the individual understand emotional experiences and their cognitive appraisal. This approach has been referred to as the unified treatment model or unified protocol and also transdiagnostic therapy (Norton & Roberge, 2017). Research studies have shown this treatment to be effective in disorders such as anxiety and depression (Carlucci et al., 2021; Sakiris & Berle, 2019).

Overall, the CBT movement sought to understand how cognitions were disordered or disrupted in mental disorders. Whereas humanistic therapies emphasized emotional processing, cognitive behavioral approaches emphasized thoughts. This includes the manner in which a person conceptualizes their life and experiences, including internal emotional experiences. The basic idea is that psychological disturbances often involve errors in thinking. One real value of many cognitive behavioral approaches is that they have been tested empirically and are presented in books and manuals that describe the steps involved in therapy.

As with other perspectives, cognitive behavioral approaches have been expanded to include several other techniques. Some of these are mindfulness approaches and dialectical behavior therapy, as discussed previously, as well as acceptance and commitment therapy (ACT) and acceptance-based behavioral therapy (ABBT). ACT and ABBT combine mindfulness with an emphasis on accepting inner experiences without judgment, along with awareness and resilience.

These approaches have been called the new way or third wave of CBT (Hayes & Hofmann, 2017; Hofmann, Sawyer, & Fang, 2010; Perkins et al., 2023). One common theme in these approaches is the role of acceptance. In each approach, clients are encouraged to not react to negative thoughts and feelings. Throughout this book, you will be introduced to the way in which these and other therapies have been used to treat specific disorders.

Three major themes—behavior and experience, neuroscience, and the evolutionary perspective—give us important perspectives for thinking about psychopathology. In addition, an integrative perspective ranging across a number of different levels of analysis provides a greater understanding of psychopathological processes. These levels range from the highest levels of environment, culture, and society to social relationships to individual behavior and experience to our sensory, motor, emotional, and cognitive systems to the physiological processes that make up our central and peripheral nervous systems to the cortical network level to the most basic level of genetics and epigenetics. The genetic level in turn takes us back up to the highest level to understand how environmental conditions influence genetic processes.

Four ideas are critical to the concept of psychopathology. First, there is a loss of freedom and ability to consider alternatives. Second, there is a loss of genuine personal contact. Third, there is a loss of connection with one’s self and the ability to live in a productive manner. Fourth, there is person distress.

Considering psychopathology from evolutionary and cultural perspectives goes beyond the traditional psychological and physiological considerations. Culture can be seen as a system of inheritance: Humans learn a variety of things from others in their culture, including skills, values, beliefs, and attitudes. For a more complete understanding of psychopathology, it is important to understand the particular rules a culture has for expressing both internal experiences and external behaviors. Overall, research suggests a close connection between cultural and evolutionary perspectives. Not only can the environment influence genetics, but genetics can also in turn influence culture. The evolutionary and cultural perspectives help us ask questions such as these: (1) Can genetic variation influence the manner in which cultural structures formalize social interactions, and how this might be related to what is considered mental illness? (2) How long, in terms of our human history, has a particular psychopathology existed? (3) What function might a disorder serve, and how did it come about? (4) How can a basic human process (e.g., the pain of social rejection) develop in relation to an earlier one (e.g., the brain circuits involved in physical pain)?

One of the main themes of the study of evolution is the manner in which organisms are in close connection with their environment. It is this close connection that allows for change, including the turning on and off of genetic processes, to take place. Humans are born less fully developed at birth than many other species and thus are sensitive to changes in their environment as they continue to develop. Unlike animals that live within nature, humans largely live within the backdrop of our culture. Another part of the complexity with humans is our ability to reflect on ourselves and our world. In this way, a layer of thought, including expectation and imagination, is injected between the person and the environment.

Mental disorders have been with us throughout our human history. Since the time that written language became a part of our experience, humans have described mental disorders. Examples of historical conceptions of psychopathology include those of Pythagoras and Hippocrates in ancient Greece and Galen from the period of the Roman Empire; advances in anatomy by da Vinci in art and Descartes in science from the Renaissance; advances in understanding the brain and nervous system in the 1700 to 1900 period; and Darwin’s description of the theory of evolution and Charcot’s classification of psychological and brain disorders in the 1800s. Historically, the care and treatment of individuals with mental illness also advanced, as did our understanding of the experience of these disorders. Although the Greeks already saw mental illness as a disorder involving the brain, it is only within the past 125 years that scientific support began to clarify this position.

Biological treatment for psychological disorders usually involves psychotropic medications, which have been expanded and improved over the past 60 years. Where medications have not been effective, other techniques are sometimes used, including ECT, TMS, and DBS.

There are currently three broad perspectives for the psychological treatment of mental disorders: the psychodynamic perspective, the existential-humanistic perspective, and the cognitive behavioral perspective. They were developed somewhat independently and often in opposition to one another. Beginning in the 1950s and 1960s, however, there was a movement to determine the effectiveness of psychological treatments in a scientific manner. Researchers and clinicians began to focus more on approaches and principles for which there was scientific evidence of effectiveness. This led to developing effective treatments for particular disorders and greater integration of techniques from the three different approaches as well as from other perspectives.

Study Resources

Review Questions

Why do stigmas arise in regard to mental illness? What impacts do stigmas have on individuals with psychopathology as well as their families, communities, and society as a whole?

Three major themes—behavior and experience, neuroscience, and the evolutionary perspective—are presented as giving us important perspectives for thinking about psychopathology. What are some of the ideas each of these perspectives offers?

What levels of analysis are important to consider in understanding psychopathology? What are the advantages of considering multiple levels and taking an integrated approach?

This chapter states that “considering psychopathology from evolutionary and cultural perspectives goes beyond the traditional psychological and physiological considerations.” What arguments does the author put forth to explain the importance of these two perspectives in asking critical questions that need to be answered? Do you agree?

What are the four critical characteristics to be included in answering the following question: What is psychopathology?

How does reading about the experiences of individuals with mental illness inform our understanding of the nature of psychopathology?

Describe how mental illness was understood in each of the following historical periods and how that understanding was advanced: ancient Greece and Rome, the Renaissance, and the 1700s to 1900s. Give examples of the individuals and ideas critical to each period.

How were individuals with mental illness treated during different historical eras? Who were some of the people who played a critical role in advancing treatment?

Descartes created a mind–body distinction that science since that time has had to address: How can a material body including the brain be influenced by an immaterial process such as the mind? How can a thought influence a cell in the brain? How would you handle the mind–body problem?

What we now know about the structure and function of the human brain and nervous system has developed throughout history. What is your model of how the brain is involved in mental illness?

Describe the contributions of the following individuals from different perspectives to the field of psychological treatment as a whole: Sigmund Freud, Hans Strupp, Carl Rogers, Leslie Greenberg, B. F. Skinner, Albert Bandura, and Aaron Beck.

CHAPTER 2

The historical considerations of psychopathology emphasized careful observation and interaction with the afflicted individuals as important methods for understanding the nature of the disorder. However, with progress in the neurosciences, brain imaging, and genetics, other levels of analysis have become possible. The new levels offer different perspectives for the field of mental illness, but because many of these discoveries are so new, it is not surprising that our understanding of the field of mental illness is currently in flux. Neuroscience research has been used to find more objective markers in the diagnosis and treatment of mental disorders. It has also helped describe cognitive, emotional, and motor processes in both health and illness. This has resulted in a better articulation of what underlies these processes, such as problems in setting goals, having relationships with others, thinking, and feeling, as well as deficits in the memory system and the reward system.

The past 40 years have brought forth new technologies that allow us to study human behavior and experience in ways not previously possible. As you will see with many of the techniques described in this chapter, sampling brain processes or genetic material is basically simple and painless for the people involved. In terms of psychopathology, by using brain imaging techniques it is possible to see how individuals with a particular mental disorder perform cognitive and emotional tasks differently from those without the disorder. We can also examine genetic differences between those with a certain disorder and those who do not show the signs and symptoms of the disorder. Further, to understand the brain and genetic levels, it is important to consider the role that evolution has played. These three approaches will be emphasized in this chapter.

One word of warning before we continue: Currently, we have no neuroscience technique that can definitively diagnose a given individual in terms of mental disorders. What we can say is that a group of individuals with a particular disorder appear to differ on certain measures compared to a group of individuals without the disorder. Even those with the same disorder may show differences in how the disorder is manifested.

To understand mental illness as a brain disease, we need methods for showing how the brain is involved in psychopathology (Andreasen, 2001). Within the past five decades, a variety of research techniques have been developed or significantly improved that allow us to better specify the nature of mental disorders from the standpoint of the brain. In this quest, there has been a strong emphasis on brain imaging, genetics, and an evolutionary perspective. In general, these approaches have allowed researchers to study individuals with mental disorders on a number of levels simultaneously.

Historically, what we now consider to be neuroscience approaches to psychopathology were limited. For example, Paul Broca in the 1800s needed to wait until his patients died before he could study the nature of their brains. In the early part of the 20th century, work with animals was the major way of understanding how the various structures of the brain influenced behavior. Some scholars such as Carl Jung added EDA to reaction time research. Jung used the word association test developed by Wilhelm Wundt to better understand psychopathology and how individuals with different disorders process cognitive and emotional information. The second part of the 20th century expanded a tradition that used psychophysiological measures such as electroencephalography (EEG) and EDA to study psychopathology. In this century, a variety of noninvasive techniques have allowed researchers and clinicians to obtain a better view of how the brain and other physiological systems function in psychopathology (see Raichle, 2011, 2015a for overviews). These will be reviewed in this chapter.

One common conviction of neuroscientists is that there is something unusual about the human brain, both in complexity and in ability, that leads to humans’ abilities to perform a variety of tasks (Northcutt & Kaas, 1995; Preuss & Kaas, 1999). The human brain has been estimated to contain 86 billion neurons and more than 100,000 kilometers of interconnections (Hofman, 2001; Goldstone, Pestilli, & Börner, 2015). Estimates in mammals suggest that a given neuron would directly connect to at least 500 other neurons and probably more. This, in turn, would suggest there are 50 trillion different connections in the human brain!

Regardless of how exact this estimate may be, the conclusion is that the human brain has an extremely complex set of networks. Neurons created before birth follow chemical or other pathways in the brain to create the necessary connections to allow for vision, hearing, and other processes. In addition, we know that neurons are also created in humans after birth. A 1-year-old infant has more neurons than they will have throughout their life. After that, neurons are gained and lost depending on use. The genetic and brain mechanisms that create and remove neurons from the developing brain play an important role in the development of mental disorders. Let us now turn to the brain itself.

In this section, you will be introduced to the basic mechanism of the brain, the neuron. Over millions and even billions of years of evolution, the neuron has served as the basic building block of many organisms ranging from jellyfish to humans. First, let’s briefly review brain anatomy.

A Quick Review of Brain Anatomy and Function

Let’s begin with some simple terms. Structures closer to the front of the brain are referred to as anterior, whereas those closer to the back are called posterior. You will also see the terms dorsal, which is toward the back side, and ventral, which is toward the belly side. The brain appears symmetrical from the top with left and right hemispheres. Structures closer to the midline dividing the left and right hemispheres are referred to as medial, whereas those farther away from the midline are called lateral (Figure 2.3).

Brain areas can be described both in terms of location and function. Looking at the left hemisphere from the side, we can describe four lobes of the brain (Figure 2.4). The frontal lobe is located at the front of the cortex and is involved in planning, higher-order cognitive processes such as thinking and problem solving, as well as moral and social judgments.

There is a cavity referred to as the central sulcus that separates the frontal lobe from the parietal lobe. The brain area behind the central sulcus receives sensory information from our body, including the experience of touch. The area in front of the central sulcus allows the muscles of our bodies to make movements such as picking up a glass. The parietal lobe, which is toward the back and at the top of the cortex, is involved in spatial processes such as knowing where you are in space and performing spatial problems. The occipital lobe is located near the back of the brain and toward the bottom. The occipital lobe is involved with the processing of visual information and receives information from our eyes. Below the frontal and parietal lobes is the temporal lobe. Looking at the brain, you can see that the frontal and temporal lobes are separated by a deep groove, which is called the lateral fissure. The temporal lobe receives information from our ears and is involved in hearing as well as aspects of language. Other parts of the temporal lobe are involved in the naming of objects from visual information processed in the occipital lobes. The areas of the brain that are associated with different functions are shown in Figure 2.5. Let us now turn to the manner in which information moves throughout the brain, with an emphasis on the neuron.

The brain’s function involves one basic element, the neuron. Although neurons come in a variety of sizes and shapes, there are some basic characteristics (as shown in Figure 2.6):

The cell body contains a nucleus, which includes deoxyribonucleic acid (DNA) and other elements including mitochondria, which are involved in supplying energy.

The axon is a slender nerve that conducts electrical impulses away from the cell body. Axons can be fairly short, as found in the human brain, or 4 or 5 feet in length, such as those that go from the spinal cord to the arms and legs.

The dendrites receive information from other cells.

The dendrites receive information from other neurons, which connect at different locations on the dendrites. Although illustrations in textbooks usually show only a few connections between neurons, there are generally thousands of these connections. Recent research has helped to change the view of the function of dendrites (Chavlis & Poirazi, 2021). Dendrites influence how neurons process information. What are called passive dendrites filter the information traveling to the cell body. This allows neurons to infer the distance of incoming signals. Active dendrites can produce signals of their own, referred to as dendritic spikes. These dendritic features amount to different types of nonlinear integration and allow individual neurons to perform complex computations. That is, they function in ways that are more complex than simply adding and subtracting the number of signals present.

The terminal branches from other neurons do not actually touch the dendrites of a given neuron; they instead make a biochemical connection through a small gap filled with fluid, which is referred to as a synapse. These biochemical connections can release molecules (ions) with an electrical charge.

As more of these electrical charges add together, it increases the size of the electrical potential. At a critical point, an action potential is produced at a location near the cell body, which travels quickly down the axon in one direction. An action potential is referred to as an “all or none” signal, since above the critical value an action potential is produced, whereas below the critical value, no electrical activity is sent down the axon.

The speed at which the action potential travels down the axon depends on two factors. The first is the width of the axon. For example, action potentials travel faster in larger diameter axons. The second factor relates to whether the axon is covered with an insulating material called the myelin sheath. Myelin is made up of fats and proteins. It wraps around axons like insulation does around electrical cables and results in an increased speed in information transmissions. Action potentials travel faster in axons surrounded by myelin. Thus, an axon with a larger diameter and wrapped in myelin would have the fastest conduction times. People with disorders such as multiple sclerosis and autism show deficits in axonal connections.

It should be noted that there are two major types of synapses. One type, referred to as a chemical synapse, involves secretion from the previous neuron of various types of neurotransmitters (Figure 2.7). These neurotransmitters create a current flow. This changes the physiological state of the next (postsynaptic) neuron such that it is more likely (excitatory) or less likely (inhibitory) to create an action potential. The second type of synapse is electrical in nature. Current flows through special channels that connect the gap between the two neurons.

Passing information from one neuron to another involves a number of steps:

Neurotransmitters need to be created and stored.

An action potential travels down the axon to the terminal.

Through a variety of processes, a neurotransmitter is released into the gap between the two neurons.

The neurotransmitter then binds with specific proteins in the next neuron.

This either increases (excitatory) or decreases (inhibitory) the possibility that the next neuron will create an action potential.

The gap between the two neurons must be made neutral at this point by any of a number of mechanisms, including making the neurotransmitter inactive, having the neurotransmitter taken up by the first neuron (referred to as reuptake), and removing the neurotransmitter from the gap between the two neurons.

It is these neurotransmitters that lead to anxiety processes in some cases but depression in others. Most medications used for treating mental illness influence the neurotransmitters at the synapses. It is also true that going to psychotherapy and learning new skills can also influence the structure and function of synaptic processes. In terms of disorders, Alzheimer’s disease, which results in memory loss, is caused by destruction of individual neurons throughout the brain (Nath et al., 2012). Most addictive drugs increase the amount of dopamine in the gap between the neurons. Thus, having an understanding of the role of neurotransmitters is important.

Major Neurotransmitters

In the chemical synapse, neurotransmitters play a critical role. Neurotransmitters transmit signals from one neuron to another. It is also the case that psychotropic medications largely have their influence at the site of the synapse. To date, more than 100 different neurotransmitters have been identified. Neurotransmitters have been classified both in terms of structure and in terms of function. Most neurons utilize more than one type of neurotransmitter for their functioning.

Regarding their structure, neurotransmitters can be classified in terms of size (Purves et al., 2013). This results in two broad categories. The first type is small molecule neurotransmitters such as glutamate, which is excitatory, and GABA (gamma-aminobutyric acid), which is inhibitory. They are often composed of single amino acids. These small molecule neurotransmitters tend to be involved in rapid synaptic functions.

Glutamate is considered to be the most important neurotransmitter in terms of normal brain function. In abnormal conditions, the firing of rapid glutamate neurons can lead to seizures in a number of areas of the brain. GABA is inhibitory, and drugs that increase the amount of GABA available are used to treat such disorders as anxiety.

The second type of neurotransmitter in terms of size is larger protein molecules referred to as neuropeptides. These can be made up of 3 to 36 amino acids. Neuropeptides tend to be involved in slower, ongoing synaptic functions.

In terms of function, neurotransmitters can also be categorized into three broad groups (Nadeau, 2004). The first group includes those neurotransmitters that mediate communication between neurons, such as glutamate and GABA. The second group includes those neurotransmitters that influence the communication of information, such as opioid peptides in the pain system. The third group includes those neurotransmitters that influence the activity of large populations of neurons, such as dopamine, adrenaline, noradrenaline, and serotonin. For example, cocaine blocks the ability of a neuron to remove the neurotransmitter dopamine from the synapse, which increases the experience of addiction. (See Table 2.1 for a description of various neurotransmitters.)

Table 2.1 Some Representative Neurotransmitters

Neurotransmitter Function

Acetylcholine Transmitter at muscles; in brain, involved in learning, etc.

Monoamines

Serotonin Involved in mood, sleep and arousal, aggression, depression, obsessive-compulsive disorder, and alcoholism.

Dopamine Contributes to movement control and promotes reinforcing effects of food, sex, and abused drugs; involved in schizophrenia and Parkinson’s disease.

Norepinephrine A hormone released during stress. Functions as a neurotransmitter in the brain to increase arousal and attentiveness to events in the environment; involved in depression.

Epinephrine A stress hormone related to norepinephrine; plays a minor role as a neurotransmitter in the brain.

Amino Acids

Glutamate The principal excitatory neurotransmitter in the brain and spinal cord. Vitally involved in learning and implicated in schizophrenia.

Gamma-aminobutyric acid (GABA) The predominant inhibitory neurotransmitter. Its receptors respond to alcohol and the class of tranquilizers called benzodiazepines. Deficiency in GABA or receptors is one cause of epilepsy.

Glycine Inhibitory transmitter in the spinal cord and lower brain. The poison strychnine causes convulsions and death by affecting glycine activity.

Neuropeptides

Endorphins Neuromodulators that reduce pain and enhance reinforcement.

Substance P Transmitter in neurons sensitive to pain.

Neuropeptide Y Initiates eating and produces metabolic shifts.

Gas

Nitric oxide One of two known gaseous transmitters, along with carbon monoxide. Can serve as a retrograde transmitter, influencing the presynaptic neuron’s release of neurotransmitters. Viagra enhances male erections by increasing nitric oxide’s ability to relax blood vessels and produce penile engorgement.

It should be noted that the same biochemical substance can be either a neurotransmitter or a hormone. If the substance is released into the gap between neurons in the brain, it is referred to as a neurotransmitter. Overall, neurotransmitters are fast acting, as they facilitate or inhibit the action potential and thus process information in the brain. If the biochemical substance is released into the blood supply, it is referred to as a hormone. In general, hormones take longer to produce effects. Changes produced by hormones are in the time frame of seconds to days, depending on the particular hormone involved.

Encoding Information

Information is encoded by means of action potentials in terms of frequency. That is, a loud sound would be encoded by a series of action potentials from the cells sensitive to sound intensity. A soft sound would result in fewer action potentials being fired. When observed in relation to a stimulus, action potentials are also referred to as spikes, and a number of spikes over time are referred to as spike trains. Figure 2.8 shows different levels of firing. Understanding the nature of spikes and how they relate to information in the brain has been an important question since the beginning of the 20th century when they were first recorded (Rieke et al., 1999).

In discussing the brain, we want to induce you to a system of communication that is gaining more relevance in neuroscience. Traditionally, the brain and the gastrointestinal system have been studied separately. However, this is changing with a new understanding of how they are connected—in particular, through bacteria.

In our bodies there are around 10 trillion microorganisms, referred to as the microbiome (P. Kelly et al., 2022; Smith & Wissel, 2019). These organisms include fungi, archaea, viruses, and bacteria. It is the bacteria that have been the focus of much study. It is estimated that 500 to 1000 species of bacteria are found in our bodies, including the gut (J. A. Gilbert et al., 2018). Besides the gut, these organisms are also found on the skin and in the mouth, nose, lungs, and genital tract. Each of these strains of bacteria has a genome of its own that contains thousands of genes. In fact, these bacteria have more genetic diversity and thus more flexibility than the human genome.

Although many people think of bacteria as harmful, they can also play an important positive role in our lives (Tuganbaev et al., 2022). Scientists are beginning to understand the role of the gut in human health, disease, and mental disorders. These bacteria in the gut (referred to as the gut biome or gut microbiome) are correlated with a wide variety of conditions. On the positive side, growing evidence is suggesting that the gut microbiome can play a role in cognition, especially executive function and verbal memory (Mayneris-Perxachs et al., 2022). On the negative side, disorders associated with the gut biome include autism spectrum disorder, depression, inflammatory bowel disease, and even cancer and Parkinson’s disease (Brown & Goldman, 2020).

Although there are specific species of bacteria, how they influence behavior and experience is complex. Some are associated with the production of such biochemical substances as GABA, while others are related to serotonin production. These chemical substances can then influence other organs, including the brain, through a number of mechanisms, including the blood system and the vagus nerve. One important player connecting the gut to the spinal cord and brain and vice versa is the vagus nerve (Needham et al., 2020). It should be noted that the gut contains the second most neurons in your body after your brain.

What is interesting is that different individuals have very different collections of these bacteria. In fact, studies have shown a relationship between the composition and diversity of microbiome in the gut and human personality traits (Johnson, 2020). Those who work on farms have a different microbiome than those who work in a big city. Surprisingly, the biome of identical twins can vary.

The composition of the human gut is influenced by actions of the immune system as well as a number of other factors. It is assumed that during and shortly after birth, the mother and other environmental factors help to establish the composition of the biome in the gut. After weaning, the human gut biome becomes fairly established and remains stable in healthy individuals. It is known that malnutrition can influence early brain development. Recent work has shown an important role for the gut microbiome in the development and function of the nervous system (Coley & Hsiao, 2021; Foster, 2022).

There is some suggestion that antibiotics taken early in life may affect the gut biome in a manner that can lead to specific disorders (Brodin, 2022; Lu & Stappenback, 2022). Later in life, major changes in diet can also influence the biome. If the person were to resume their original diet, then the original biome would reappear. However, the microbiome also changes with aging (Bana & Cabreiro, 2019), and sleep deprivation and stress can influence the gut biome in a negative manner that increases inflammation. Other lifestyle changes such as exercise appear to influence the structure of the biome by reducing inflammation, thus improving health. Gut bacteria in childhood is also associated with asthma and allergic reaction in later life.

Current research has also examined weight and the biome. The gut biome is associated with whether the person is lean or obese (Walters et al., 2014). Other studies have shown how the brain and gastrointestinal system communicate in order to regulate energy homeostasis (Clemmensen et al., 2017; Cryan & Mazmanian, 2022). New research is examining ways to influence this communication through the gut biome as a potential treatment for obesity. The modulation of the gut biome can also offer treatment for certain psychological states. One study showed differences in brain activity related to social stress in participants who received a particular probiotic that contained a live beneficial bacteria for 4 weeks versus those who received a placebo (H. Wang et al., 2019). Another similar study gave medical students probiotics for 12 weeks leading up to their qualifying exams and showed reductions in stress-related symptoms (Nishida et al., 2017). We will describe specific psychopathological disorders and their relation to the microbiome in separate chapters in this book.

Let us now move from the consideration of neurons and neurotransmission to an overview of some of the specific neuroscience techniques that are used to understand psychopathological processes. Following an examination of these neuroscience techniques, we will move to a discussion of the networks of the brain.

Describe the major techniques used to view the human brain at work, and their related ethical implications.

With 86 billion neurons and 50 to 200 trillion connections between neurons in the human brain, understanding these connections on a neuronal level would be an impossible task. However, scientists have been able to use the manner in which neurons work as a window into their function. A variety of techniques for observing activity in the brain have been developed.

Currently, the major types of brain imaging techniques are electroencephalography (EEG), magnetoencephalography (MEG), positron emission tomography (PET), and functional magnetic resonance imaging (fMRI). EEG is a technique for recording electrical activity from the scalp related to cortical activity. MEG measures the small magnetic field gradients exiting and entering the surface of the head that are produced when neurons are active. PET is a measure related to blood flow in the brain, which reflects cognitive processing. fMRI is based on the fact that blood flow increases in active areas of the cortex. It is also possible to use the magnetic resonance imaging (MRI) magnet to measure cortical connections in the brain, which is referred to as diffusion tensor imaging (DTI). Let’s take a look at each of these techniques, and consider the strengths and weaknesses of each type.

Electroencephalography

Electroencephalography (EEG) is a technique for recording electrical activity from the scalp related to cortical activity. It reflects the electrical activity of the brain at the level of the synapse (Nunez & Srinivasan, 2006). It records the product of the changing excitatory and inhibitory currents. Action potentials contribute very little to the EEG. However, since changes at the synapse do influence the production of action potentials, there is an association of EEG with spike trains (Whittingstall & Logothetis, 2009).

The EEG was first demonstrated in humans by Hans Berger in 1924, and results were published 5 years later (Berger, 1929/1969). Since the neurons of the brain and their connections are constantly active, EEG can be measured during both waking hours and sleep. In fact, EEG serves as an objective measure of depth of sleep (Figure 2.9).

EEG can be measured with only two electrodes or as a high-density array of more than 200 electrodes. EEG activity has been used to infer brain processing. The actual measure of EEG is the difference between the signals at any two electrodes. Traditionally, the second or reference electrode was placed at a location not considered to produce electrical signals, for example, the ear lobe. Today, a common practice is to average the signals in all of the electrodes available and compare that with each specific electrode.

Some aspects of the EEG signal may appear almost random, while other fluctuations appear periodic. Using signal processing techniques, it is possible to determine the major frequency and amplitude seen in the signal. Amplitude refers to how large the signal is, and frequency refers to how fast the signal cycles, measured in cycles per second, or Hertz (Hz). Over the years, researchers have noticed that specific patterns of EEG activity were associated with a variety of psychological states (Figure 2.10). When an individual is relaxed with their eyes closed, high-amplitude regular activity is seen in the EEG at a frequency of 8 to 12 Hz. Alpha activity in the 8- to 12-Hz range was the first pattern of EEG activity Berger noted. If the person begins to perform some mental activity such as mental arithmetic, lower-amplitude EEG is seen at a higher frequency, above 20 Hz, and is referred to as beta activity.

EEG oscillations are one way in which information is transferred in the brain (Knyazev, 2007). For example, theta oscillations are associated with memory performance (Liebe et al., 2012). Theta is also involved in coordinating emotional information between the limbic areas and the frontal areas of the brain. Delta oscillations are seen in sleep and motivational processes such as drug use. Drugs such as cocaine produce changes in a number of EEG frequency bands. Alpha oscillations, on the other hand, are involved in inhibiting the activity of various brain areas.

In recent years, researchers have become interested in the processing of a percept (Singer, 2009; Singer & Gray, 1995; Tallon-Baudry & Bertrand, 1999). For example, when one sees a black and white spotted Dalmatian dog against a black and white background, there is usually a subjective experience of having the image “pop out.” Associated with this perception is a burst of EEG gamma activity. Figure 2.11 compares the amount of EEG gamma activity in those individuals trained to see the Dalmatian as compared with those who were not trained.

Evoked Potentials

Event-related potentials (ERPs), also known as evoked potentials (EPs), show EEG activity in relation to a particular event. Imagine taking a continuous EEG signal during which a picture or tone is presented to an individual a number of times. If we were to take the EEG in the half-second following the stimulus presentation and average these together, we would have the brain response to the stimulus (Figure 2.12).

The waveform of the ERP is described in terms of positive and negative peaks and the time elapsed from the stimulus presentation. Thus, a P300 waveform is a peak in the ERP in the positive direction occurring 300 milliseconds (ms) after the stimulus presentation. Likewise, N100 would be a peak in the negative direction 100 ms after the stimulus presentation. Based on early recording equipment characteristics, positive peaks are often shown pointing downward and negative peaks upward. For simplicity, P300 is sometimes referred to as P3, since it represents the third positive peak following a stimulus presentation. Thus, one may see both N1 or P3 as well as N100 or P300 used in the literature.

Evoked potentials offer a view of cognitive and emotional processing that takes place in the brain outside of awareness. They are also useful in groups such as infants who cannot respond verbally. In one study, evoked potentials were recorded from 7-month-old infants as they saw faces with emotional expressions. A stronger reaction was seen at around 400 ms when they saw a fearful face as opposed to a happy face (Taylor-Colls & Pasco Fearon, 2015). A common use of evoked potential research in terms of mental disorders has been to show how cognitive and emotional processing differs for those with a disorder and those without. Evoked potentials have also been used to distinguish those with schizophrenia from those without (Laton et al., 2014). In addition, evoked potentials have shown that children with ADHD (attention deficit/hyperactivity disorder) show different types of evoked potential components from those with autism spectrum disorder (Tye et al., 2014).

Magnetoencephalography

Magnetoencephalography (MEG) measures the small magnetic field gradients exiting and entering the surface of the head that are produced when neurons are active. It uses a SQUID (superconducting quantum interference device) to detect small magnetic activity that results from the activity of neurons. As shown in the photo, the person simply puts their head in a device that contains magnetic sensors.

MEG signals are similar to EEG signals but have one important advantage that stems from the fact that magnetic fields are not distorted when they pass through the cortex and the skull. This makes it possible to be more accurate in terms of spatial location of the signal with MEG. For example, youth with bipolar disorder show greater activation in the frontal gyrus and less in the insula following negative feedback than do control participants (Rich et al., 2011).

Positron Emission Tomography

Positron emission tomography (PET) measures variations in cerebral blood flow that are correlated with brain activity. It is through blood flow that the brain obtains the oxygen and glucose from which it gets its energy. By measuring changes in blood flow in different brain areas, it is possible to infer which areas of the brain are more or less active during particular tasks. Blood flow using PET is measured after participants inhale, or are injected with, a tracer (a radioactive isotope) that travels in the bloodstream and is recorded by the PET scanner (a gamma ray detector). Figure 2.13 depicts a PET scan in which individuals with schizophrenia show less metabolism in the frontal lobes as compared with healthy controls (Buchsbaum & Haier, 1987).

The general procedure is to make a measurement during a control task that is subtracted from the reading taken during an experimental task. Although it takes some time to make a PET reading, which reduces its value in terms of temporal resolution, it is possible to determine specific areas of the brain active during different types of processing. Since PET can measure almost any molecule that can be radioactively labeled, it can be used to answer specific questions about perfusion, metabolism, and neurotransmitter turnover.

Some of PET’s main disadvantages include expense; the need for a cyclotron to create radioactive agents; the injection of radioactive tracers, which limit the number of experimental sessions that can be run for a given individual; and limited temporal resolution. Due to risks associated with exposure to the radioactive tracer elements in a PET study, participants typically do not participate in more than one study per year, which limits the degree to which short-term treatment efficacy can be studied. With the development of fMRI, PET is no longer the technique of choice for research studies in psychopathology.

However, PET does offer an advantage for studying specific receptors such as dopamine receptors in the brain, which are particularly active in those with an addiction or inactive in those with Parkinson’s disease. Another study used PET to examine serotonin in those with social anxiety disorder (Frick et al., 2015). An overactive serotonin system was found at the synaptic level in those with social anxiety disorder as compared to matched controls.

Functional Magnetic Resonance Imaging

Functional magnetic resonance imaging (fMRI) is based on the fact that blood flow increases in active areas of the cortex. Specifically, hemoglobin, which carries oxygen in the bloodstream, has different magnetic properties before and after oxygen is absorbed. Thus, by measuring the ratio of hemoglobin with and without oxygen, the fMRI is able to map changes in cortical blood and infer neuronal activity. Measurements using fMRI are made by having a person lie on their back inside a large magnet and radio frequency device, which measures changes in blood oxygen levels.

In contrast to an fMRI, an MRI creates only a structural image MRI, like an X-ray, that shows the anatomy of the brain but does not reflect activity (Figure 2.14). It is possible to measure brain areas with an MRI in terms of size. Often, measures of those with a disorder are compared to those without the disorder. For example, reduction in brain volume is seen in a variety of disorders, including schizophrenia. These measures can be determined from the MRI.

Brain activity can be determined with the fMRI, or functional MRI. A common procedure for showing brain activity is to take a baseline in which the patient just relaxes. Following this baseline period, the patient performs specific tasks. The fMRI response recorded during the task is subtracted from that during the baseline period. This shows which specific areas of the brain are involved in performing a task. This information is then placed on the structural MRI image of the brain as shown in Figure 2.15. The color used reflects the amount of activity seen in a particular brain area. As you will see throughout this book, fMRI has been used with almost every disorder discussed. You can also compare one group of individuals with another. For example, Figure 2.16 shows that women with post-traumatic stress disorder (PTSD) activate different areas of the brain (the amygdala and insula) when processing emotional information compared with women without PTSD (Bruce et al., 2013).

It is also possible to use the MRI magnet to measure cortical connections in the brain, which is referred to as diffusion tensor imaging (DTI). DTI is available with most MRI imaging systems (see Thomason & Thompson, 2011; Waszczuk et al., 2021, for overviews of DTI and psychopathology). It is a procedure for showing fiber tracts (white matter) in the brain. This information can then be visualized by color coding it as shown in Figures 2.17 and 2.18. This allows one to map the white matter connections in the brain. In these figures, the connections between different parts of the brain can be seen.

Developmentally, after-infancy measures of white matter suggest a linear development until a person is in their 30s. Following a plateau, these gradually decline with age. Using DTI, it is possible to map the mild cognitive impairment seen in dementia and the more severe impairment seen in Alzheimer’s disease. Disconnections are seen between the major areas involved in memory, such as the hippocampus and the temporal lobes (Stebbins & Murphy, 2009). As would be expected, this loss of connectivity is greater in Alzheimer’s than in mild cognitive impairment. Individuals with schizophrenia also exhibit problems with cortical connections (Phillips et al., 2011). It is also possible to compare the structure of pathways in the brain between humans and other primate species (Wedeen et al., 2012). DTI and other brain imaging techniques have also given us a better understanding of cultural differences as described in Cultural LENS: Using Brain Imaging to Understand Culture.

Spatial and Temporal Resolution

There are a number of trade-offs that researchers must consider when choosing a brain imaging technique (see Table 2.2 for pros and cons of using the different techniques). It begins with the research question one is asking. If you wanted to know if the areas of the brain associated with memory, such as the hippocampus, are larger or smaller in individuals with PTSD, then you would want a measure of structure. If you wanted to know if those with autism quickly viewed different emotional faces in a different way, then you would want a measure that reflects changes in brain processes.

Table 2.2 Pros and Cons of Different Neuroscience Techniques

Technique Pros Cons

EEG Reflects quick changes in the brain, inexpensive, not invasive, safe, little discomfort Difficult to know which brain areas produced the EEG

MEG Reflects quick changes in the brain, not invasive, safe, no discomfort Basic equipment is expensive

MRI and fMRI More exact location of structure and activity, safe, little discomfort Basic equipment is expensive, cannot be used with people who have any metal in their body (heart pacemaker or metal pins), fMRI not able to measure short-term changes in the brain

PET Able to measure specific neurotransmitters Basic equipment is expensive, injection of radioactive tracers limits number of scans per year, not able to measure short-term changes in the brain

One important question is how fast a particular technique can measure change. This is referred to as temporal resolution. EEG and MEG, for example, can measure quick changes in the brain on the millisecond level. PET, on the other hand, can only record changes that take place in a period of a few minutes or more. Another consideration is spatial resolution, that is, what size of brain area a technique can measure. PET and fMRI are better able to pinpoint the location of activity in the brain, whereas with EEG it is less possible to know specifically where in the brain activity came from. The relationship between spatial and temporal resolution is shown in Figure 2.19.

Neuroethics

When we read in the news about discoveries in the neurosciences, they are often presented in an optimistic manner. We are told they will help us treat medical disorders or learn more about how we think and feel. This is true. However, traditionally, societies have based codes of conduct and the law on observable behaviors. An important question currently being asked is who should have access to data and scans of your internal processes. LENS: Neuroethics: Ethical Considerations When Using Neuroscience Techniques examines the field of inquiry that is asking these questions. It is referred to as neuroethics.

Given that the human brain has some 86 billion neurons with some 5,000 synapses, each resulting in trillions of synaptic connections, it is clear that a higher-level analysis of brain function is necessary (Goldstone et al., 2015; Herbet & Duffau, 2020). A variety of brain imaging techniques have allowed for a network analysis that describes which areas of the brain are involved in specific tasks. The first step has been to describe the normal processing of networks such as those involved in rewards or fear. The next step is to understand how these networks become involved in more psychopathological states such as addiction and anxiety. The goal now is to better understand how the basic network becomes involved in psychopathological processes. Is it a lack of connections between brain areas, or is there a reorganization of normal processes that underlies specific psychopathologies? This is one question scientists are asking.

Following the discovery of brain areas involved in particular functions, such as Broca’s area, in the 1800s, researchers searched for specific areas involved in particular cognitive, emotional, and motor processes. With the increased sophistication of brain imaging technologies came a greater ability to view the manner in which certain parts of the brain work together as well as large-scale turning off and on of various areas. Some processes involve a pathway using only a few neurons. Being startled by a loud noise or touching a hot stove are examples of processes that have short neuronal pathways. Other processes use a more complex series of connections. More voluntary and complex processes use a much larger series of neuronal connections referred to as networks.

Researchers examine how specific brain areas work together as networks. This search has also extended to psychopathology. Psychopathology can be seen in terms of problems involving either particular brain areas or the connections between areas that make up the network.

We all experience the brain organizing itself in terms of various networks throughout our day. One of the most familiar is sleep. Another is waiting for a lecture to start, when we just let our mind wander. Both of these cases are not responses to external stimuli but are self-organizing processes that occur. These types of processes are controlled by a large number of neurons working together in the form of a network.

Networks allow our brains to process information efficiently (Khona & Fiete, 2022; Laughlin & Sejnowski, 2003; Sporns, 2011, 2022). Overall, cortical networks are influenced by experience and designed to be efficient in terms of connections between neurons in the network. This efficiency allows for less use of energy. One way energy is conserved is through not having every neuron connect with every other neuron.

Neurons Connect in a Network

How are neurons connected in a network? The answer may seem strange. Neurons are neither totally random in their connections with other neurons nor totally patterned. It appears that neurons are connected to one another in the same way that all humans on this planet are socially connected.

In the 1960s, the social psychologist Stanley Milgram (Travers & Milgram, 1969) asked the question, “What is the probability that any two people randomly selected from a large population of individuals such as the United States would know each other?” He answered this question by giving an individual a letter addressed to another person somewhere in the United States. This individual was to send the letter to someone they knew who might know the other person. In turn, this person was to send the letter to someone they knew who might know the person. Surprisingly, it only required five or six different people for the letter to go from the first individual to the final individual. This phenomenon has been referred to as the small world problem; more recently, the phrase six degrees of separation has been used.

Various studies have shown that the neurons in the brain can also be considered within a small world framework (Sporns, 2011). Neurons have numerous short-distance local connections, which, taken together, can be considered as a hub or module. From these hubs extend more long-distance connections to other hubs.

Local hubs can be made up of neurons that connect with each other over very short distances. Such connections are seen in gray matter. Underlying this are the axons, which transfer information throughout the brain. Their myelin sheaths are lighter in color, and thus, these areas are referred to as white matter. About 44% of the human brain is white matter. White matter generally represents longer connections between neurons. This allows for cortical networks over larger areas of the brain. Knowing this, it is possible to examine the network connections in individuals with a particular disorder and their matched controls. For example, individuals with schizophrenia have been shown to have disrupted global networks of the brain (O. Wang et al., 2012) as have those with depression (Li et al., 2018).

Networks have been studied in terms of a variety of cognitive and emotional tasks (Bressler & Menon, 2010; Raichle, 2015a). These include separate networks involved in the processing of visual or auditory information, sensorimotor processes, attentional processes, executive control, salience, and default mode (Figure 2.21).

Three of these networks have been examined in terms of psychopathology (Menon, 2011). These are the default or intrinsic network, the central executive network, and the salience network. The default network is active when an individual is not performing a particular task, such as when one’s mind wanders or is processing internal information. The central executive network is involved in higher-order cognitive and attentional tasks. The salience network is important for monitoring critical external events as well as internal states. As will be described throughout this text, psychopathological disorders such as schizophrenia, depression, anxiety, dementia, and autism have been shown to involve problems in turning networks on or off as well as problems in the connections within the network itself.

What Is the Brain’s Default (Intrinsic) Network?

What does your brain do when you are just sitting and waiting or daydreaming or talking to yourself? This is a question that is just now beginning to be explored. In psychology, most of the research you read about involves a person doing something. Reacting to emotional pictures or solving cognitive problems are common examples. In these cases, one’s attention is focused on a task in the external world.

In the same way that the brain is organized to process spatial and verbal material differently and involve different cortical networks, it also appears that different circuits are involved with internal versus external information. A variety of studies have examined brain imaging procedures in which individuals performed internal tasks versus external tasks (e.g., Ray & Cole, 1985).

However, we all know that even without an external task to do, our mind is constantly working. It jumps from one thought to another. The psychologist William James called this process the stream of consciousness. Recent researchers have referred to this process as mind wandering.

Those neural networks that are active during internal processing have come to be referred to as the brain’s default or intrinsic network (Buckner et al., 2008; Buckner & DiNicola, 2019; Raichle, 2011; Raichle & Snyder, 2007). It has been suggested that intrinsic is a better term than default, since a variety of internal tasks use this network (C. Kelly et al., 2012). The default network is separate from, but it can be understood as similar to other networks, such as those involved in visual perception or motor activities. It is made up of a set of interacting brain regions. Those areas involved represent periods of brain imaging when individuals are not engaged in any active task.

Overall, the default network is involved during internal or private considerations that do not require processing external sensory information. In fact, it appears as if there is a negative correlation between activities in the default network versus networks associated with processing information from the environment. That is, when someone begins some cognitive activity, then new networks associated with that task become active and the default network becomes less active. This suggests that separate brain mechanisms evolved for dealing with information involving the external environment as opposed to considerations internal to the person. A variety of psychopathology disorders show problems with the default network in terms of being able to turn it off and engage in a more active external task. People with schizophrenia, ADHD, and autism are groups that have difficulty turning off the default network and moving to an active task that uses a different network.

Different Networks Are Involved in Different Tasks

The central executive network is involved in performing such tasks as planning, goal setting, directing attention, performing, inhibiting the management of actions, and coding representations in working memory (Eisenberg & Berman, 2010). These are sometimes referred to as frontal lobe tasks, since damage to the frontal areas of the brain compromises performance of these tasks. These tasks are also referred to as executive functions, because they assist in planning, understanding new situations, and having cognitive flexibility. The salience network, as the name implies, is involved in monitoring and noting important (i.e., salient) changes in biological and cognitive systems.

Figure 2.22 shows those areas of the brain that Menon (2011) found to be associated with each of these networks. The figure shows an MRI structural image of the brain in black and white. The areas that are activated during the task are displayed in color. The brain is shown in terms of a three-dimensional image along an x-, y-, and z-axis. The x-axis shows the brain from the side, the y-axis from the back, and the z-axis from above. The numbers below the image represent the location along each axis. Using these three numbers, brain imaging programs can identify the areas in relation to traditional anatomical structures.

In Figure 2.22, the central executive network, which is involved in higher-order cognitive and attentional demands, including planning for the future and remembering concepts, is shown in blue. The salience network, which is important for monitoring critical external events and internal states, is shown in yellow. The default network, which is active during mind wandering and when the person is not engaged in active problem solving, is shown in red.

Let’s take a moment to understand how researchers describe brain function in terms of networks. One important concept is modularity. Modularity describes how specific areas of the brain are dedicated to certain types of processing. For example, as discussed early in the chapter, we know that a particular part of the temporal lobe, the fusiform face area, is involved in processing responses to the human face. fMRI measures, for example, would show greater brain activation in this area when observing the human face as opposed to nonhuman faces.

Another important concept is connectivity. This asks how different areas of the brain work together in specific conditions. To determine connectivity, researchers examine fMRI or EEG measures from a large number of locations throughout the brain. It is assumed that those areas whose activity is correlated are in some way working together.

The three networks—default, executive, and salience—show deficits in individuals with specific psychopathologies. Menon (2011; Menon et al., 2023) has reviewed the research literature and suggests that these networks play a prominent role in schizophrenia, depression, anxiety, dementia, and autism. As you will see throughout this book, the role of these networks may be dysfunctional in the network itself or in the ability to activate or deactivate specific networks in changing situations.

In this section, we consider the genetic level of analysis. This discussion includes a historical understanding of the study of genes as well as their structure. You will then learn about the role of DNA, genes’ influence on behavior, epigenetics, mitochondria, and endophenotypes.

Genes form the blueprint that determines what an organism is to become. Specific sets of genes have been associated with a variety of disorders, as will be described throughout this book. It was initially assumed that one day genes would be able to explain the development of psychopathology, especially schizophrenia. However, after decades of research, it is clear that simple genetic explanations are not forthcoming. Psychological disorders are related to many genetic differences, each having a small effect (Plomin, 2018). Many of the genes that are related to problems of mental illness are also involved in normal development. What has become apparent is that there is a complex interaction of genetic and environmental factors involved in mental illness.

The Historical Study of Genetics

The study of genetics begins with the work of Gregor Mendel (1822–1884). Being curious as to how plants obtain atypical characteristics, Mendel performed a series of experiments with the garden pea plant. Peas are a self-fertilizing plant, which means that the male and female aspects needed for reproduction develop in different parts of the same flower. Therefore, successive generations of peas are similar to their parents in terms of particular traits, such as their height or the color of their flowers.

Mendel found that when combining peas that have white flowers with those with purple flowers, the next generation had all purple flowers. Allowing this generation to self-fertilize brought forth plants that had purple flowers but also some that had white flowers. Mendel explained these findings by suggesting that a plant inherits information from each parent, the male and female aspects. Mendel was hypothesizing that information must be conveyed. He further suggested that one unit of information could be dominant in comparison to the other, which we now call a recessive trait. In this case, the unit of information that coded for purple would be dominant.

Mendel did not know about genes but hypothesized the existence of a specific structure he called elements. From his experiments, he determined the basic principle that there are two elements of heredity for each trait (e.g., color in the previous example). Mendel also assumed that one of these elements can dominate the other and if the dominant element is present, then the trait will also be present. In addition, Mendel suggested that these elements can be nondominant, or recessive. For the trait to appear, both of these nondominant elements must be present. These ideas are referred to as Mendel’s first law or the law of segregation.

Put in today’s language, Mendel suggested that variants of a specific gene exist, which account for variations in inherited characteristics, and that an organism receives one of these from each parent. Further, one of these can be dominant or recessive, which determines which characteristics are expressed. Mendel also realized that the inheritance of the gene of one trait is not affected by the inheritance of the gene for another trait. In the previous example illustrating the inheritance of color and height, those factors influencing color do not affect height, and vice versa. That is, the probability for each occurs separately. This is known as Mendel’s second law or the law of independent assortment.

Since Mendel’s time, we have learned a great deal about the process of inheritance. What he referred to as elements or units of information, we now call genes (Figure 2.23). We also know that genes can have alternative forms, which we call alleles. Independent researchers, Walter Sutton and Theodore Boveri, in 1903 put forth a theory we now accept as fact, that genes are carried on chromosomes. We now know that each of the approximately 20,000 human genes occurs at a specific site, called a locus, on one of our 23 different pairs of chromosomes. As genetics progressed in the 20th century, it was necessary to go beyond the two laws suggested by Mendel to a more complex understanding of how traits are passed from generation to generation. For example, if two genes are located close to one another on the same chromosome, then the result is different from that predicted by Mendel’s second law.

What Do Genes Do?

Genes form the blueprint to describe what an organism is to become. Over our evolutionary history, a majority of human genes reflect little variation. In fact, you are the same as every other human being in over 99% of your genes (Plomin, 2018). This is why all humans have two eyes and one nose and one mouth. However, perhaps one fourth of all genes allow for variation. What makes things interesting is that the two genes of these pairs are usually slightly different. The technical name for the unique molecular form of the same gene is an allele. It has been estimated that of our approximately 20,000 to 21,000 genes, some 6,000 exist in different versions or alleles (Zimmer, 2001). Current research suggests that the high heritability of mental disorders is related to many genetic differences, each having a small effect (Plomin, 2018).

When a person has two copies of the same allele, they are said to be homozygotes or homozygous for that allele. If, on the other hand, they have two different alleles for a particular gene, they are said to be heterozygotes or heterozygous for those alleles. Given that the alleles that come from your mother may not result in exactly the same characteristics as those from your father, variation is possible. It is these variations that allow for the process of natural selection to have its effect.

The job of a gene is to lay out the process by which a particular protein is made. That is, each gene is able to encode a protein, influencing its production. Proteins, which do the work of the body, are involved in a variety of processes. Functionally, proteins in the form of enzymes are able to make metabolic events speed up, whereas structural proteins are involved in building body parts. Proteins are diverse and complex and are found in the foods we eat as well as made by our cells from some 20 amino acids. Proteins serve as signals for changes in cell activity as illustrated by hormones. Proteins are also involved in health and disease as well as in development and aging.

Although the cells in the body carry the full set of genetic information, only a limited amount is expressed at any one time related to the function of the cell. That is to say, although a large variety of proteins could be produced at any one time, there is selectivity as to what is produced relative to internal and external conditions. Further, the location of the genes makes a difference in that cells in the brain produce different proteins from those in the muscles, or liver, or heart.

A gene is turned on (produces the protein) or turned off (does not produce the protein) relative to specific events. Just because a person has a specific gene does not mean that it will necessarily be expressed. The environment in which a person develops and lives plays an important role in gene expression. Even identical twins with the same genotype can display different phenotypes (defined in the next paragraph) if their environmental conditions differ during their development. For example, if one was to grow up in a high mountain range and the other in a desert below sea level, important physiological differences such as lung capacity and function would be apparent. There are few factors other than blood type in terms of human processes that can be explained totally by genetic factors alone. It is equally true that few human processes can be explained totally by the environment.

DNA

With the discovery of the structure of DNA by James Watson and Francis Crick in 1953, specifying the method by which genetic material was copied became possible. Deoxyribonucleic acid (DNA) provides information necessary to produce proteins. Proteins can be viewed as a link between the genotype (complete genetic composition of an organism) and the phenotype (an organism’s observable characteristics). Moving the genotype to the phenotype initially begins in two steps. First, the information in DNA is encoded in ribonucleic acid (RNA). Second, this information in RNA determines the sequence of amino acids, which are the building blocks of proteins. Technically, the DNA synthesis of RNA is called transcription, whereas the step from RNA to protein is called translation. RNA is like DNA except its structure is a single strand, whereas DNA has a double strand. Once encoded, the RNA goes to a part of the cell capable of producing proteins. Proteins are produced by putting together amino acids.

To be more specific, DNA represents the chemical building blocks, or nucleotides, that store information. There are only four types of bases for this coding. DNA molecules are composed of two strands that twist together in a spiral manner. The strands consist of a sugar phosphate backbone to which the bases are attached. Each strand consists of four types of nucleotides that are the same except for one component, a nitrogen-containing base. The four bases are adenine, guanine, thymine, and cytosine. These are generally referred to as A, G, T, and C. To give you some sense of size, each full twist of the DNA double helix is 3.4 nanometers (i.e., one billionth of a meter). Said in other terms, if we took the DNA in the 46 chromosomes of a single human cell and stretched it out, it would be around 6 feet long. This measurement gives you some idea of the thinness of DNA.

DNA, which is the information storage molecule, transfers information to RNA, which is the information transfer molecule, to produce a particular protein. Further, change in the rate at which RNA is transcribed controls the rate at which genes produce proteins. The expression rate of different genes in the same genome may vary from 0 to approximately 100,000 proteins per second. Thus, not only do genes produce proteins, but they do so at different rates. The crucial question becomes what causes a gene to turn on or off.

Genome is the name given to the complete set of genes in a given cell. The Human Genome Project was started in 1990 by the United States with the goal of mapping all the genes of the human body. It was an international project that was declared complete in 2003. The estimation at that time was that there are approximately 20,500 genes in a human cell.

How Do Genes Influence Behavior?

In terms of behavior and experience, the production of proteins can be transitory. For example, touching a cat’s whiskers causes changes in gene expression in the cells of the sensory cortex of the brain (Mack & Mack, 1992). This is just a momentary change. Changes can also be long term. Turning on one set of genes may have lasting influence on the ability of other genes to produce specific proteins. For example, when a songbird first hears the specific song of its species, a particular set of genes comes into play, which, once set, determine the song produced by that bird for its entire life. This process has been mapped by a number of researchers (see, e.g., Mello et al., 1992; Ribeiro & Mello, 2000). Likewise, raising mice in an enriched environment—that is, one with lots of toys and stimulation—will cause increased gene expression in genes that are associated with learning and memory (Rampon et al., 2000).

How do we know which genes are involved? In the Rampon et al. (2000) study, the genes of mice in enriched environments were compared with those of control mice who did not have this experience. Another way to know which genes are involved in a process is to actually change the genes in a particular organism. So-called “knockout” mice are genetically engineered to have particular genes turned off by breeding them in specific ways. Research shows that simple genetic changes made experimentally in animals can result in protein changes that influence social behavior. Some examples of such behaviors are increased fear and anxiety, increased grooming, hyperactivity, and even increased alcohol consumption when stressed.

As researchers studied how genes turn on and off and what factors influence this, the story became even more complicated: The processes that determine which genes turn on and off could themselves be passed on to the next generation. Of course, which factors turn the genes on and off are largely influenced by the environment of the organism. Thus, although the genes themselves could not be influenced by the environment, it was possible for the environment to influence future generations through its changes to those processes that turn genes on and off. This is referred to as epigenetics.

Epigenetic Processes

One basic idea from Mendelian genetics was that genes are not changed by experience. What is passed on, except in the case of damage to the gene, is exactly the same gene that was received by the organism from its parents. This came to be called the central dogma of molecular biology as described by Crick. He basically stated that information flow was one-directional. That is, it went from the gene to the protein. What came to be called reverse translation was seen as impossible. Thus, the gene could not be influenced or changed by changes in proteins. This was the basic view from the 1950s until very recently.

As researchers became interested in how genes turn on and off and what factors influence this, it became apparent that the story was more complicated. It was discovered that the processes that determine which genes turn on and off could themselves be passed on to the next generation. Of course, which factors turn the genes on and off are largely influenced by the environment of the organism. Thus, although DNA itself could not be influenced by the environment, it was possible for the environment to influence future generations through its changes to those processes that turn genes on and off.

This possibility of another form of inheritance came to be called epigenetic inheritance (Cavalli & Heard, 2019; Hallgrímsson & Hall, 2011; Nestler, 2011; Ospelt, 2022). Instead of actually changing the gene itself, epigenetic modifications mark a gene. This alters how it is turned on and off. Briefly, DNA is wrapped around clusters of proteins called histones. These are further bundled into structures called chromosomes. Being tightly packed keeps genes in an inactive state by preventing access to processes that turn genes on. When action is needed, a section of DNA unfurls and the gene turns on. Whether a segment is relaxed and able to be activated or condensed, resulting in no action, is influenced by epigenetic marks or tags (Figure 2.24). As a tag, histone acetylation tends to promote gene activity and is called a writer. Histone methylation and DNA methylation tend to inhibit it and are called erasers.

The environment can influence these writer and eraser tags. Tags help an organism respond to a changing environment. Some tags last a short time, whereas others can last a lifetime. In a now classic study, researchers observed that some rat mothers displayed high levels of nurturing behavior, licking and grooming their pups, while others were less diligent (Weaver et al., 2004). Behaviorally, the offspring of the more active mothers were less anxious and produced less stress hormone when disturbed than pups cared for by more passive mothers. Further, the females raised by nurturing mothers became nurturing mothers themselves.

The intriguing part of this study is that the offspring of the rat mothers who showed more licking and grooming differed in epigenetic factors. Pups raised by passive mothers showed more DNA methylation than aggressively groomed pups in the regulatory sequences of a gene encoding the glucocorticoid receptor, which is a protein present in most cells in the body that mediates an animal’s response to the stress hormone cortisol. This excessive methylation was detected in the hippocampus, a brain region involved in learning and memory, and this causes nerve cells to make less of the receptor. Activation of the glucocorticoid receptor in the hippocampus actually signals the body to slow production of cortisol. The epigenetic reduction in receptor number exacerbated the stress response in the animals. This made the animals more anxious and fearful. Further, these traits persisted throughout their lifetime. Overall, attentive mothers cause the methyl marks to be removed. Inattentive mothers, on the other hand, cause methyl marks to be added. Thus, rats inherit certain behaviors based on experience. The genes had not changed, but the tags had.

At this point, a variety of studies have shown other examples of epigenetic mechanisms at work. For example, the diet of a mouse mother before conception can influence the hair color of her infants and even her infants’ infants (e.g., Cropley et al., 2006). One interesting aspect of this research is the suggestion that a mother’s diet can influence future generations, independent of later changes in diet.

Fathers can also influence their offspring. It has been shown that a mouse will develop a diabetes-like disease if its father’s diet before the mouse’s conception was high in fat (Skinner, 2010). Also, if a mouse father is overweight, then gene activity in the pancreas of the father’s offspring will be abnormal (Ng et al., 2010). Since the pancreas makes insulin, which regulates blood sugar, this may set up the possibility of future diabetes. The opposite is also the case. If the father’s diet results in an underweight condition, then genes in the liver associated with fat and cholesterol synthesis are more active in the father’s offspring (Carone et al., 2010). Another study suggested that whether a human father smoked early in life was associated with his sons being heavier in weight at age 9 (Pembrey et al., 2006).

Overall, this type of research implies that behavior and environmental experiences at critical periods could later influence characteristics for future generations (Keverne, 2015. Current health research related to such disorders as diabetes and cancer, as well as types of psychopathology, is suggestive of such a relationship (see Katsnelson, 2010; O’Donnell & Meaney, 2020; van Os, 2010, for overviews). Both addiction and depression have been shown to have an epigenetic component (Nestler, 2011). Likewise, schizophrenia and bipolar disorder can be influenced by epigenetic processes (Jeremian et al., 2022; Varela et al., 2022). Thus, epigenetic inheritance, which involves tags or marks that determine when genes are turned off or on, offers a parallel track to traditional Mendelian inheritance for influencing phenotypes. Further, a new area of research uses identical twins to study specific epigenetic mechanisms with the goal of determining how genetic and environmental factors influence epigenetics (e.g., Bell & Spector, 2011; Tan, 2019). This approach may offer better insight into the expression of complex traits as seen in normal and psychopathological processes.

Mitochondria and Mitochondrial Inheritance

Mitochondria are structures within a cell that are involved in the production of energy. It is assumed that mitochondria descended from bacteria that began to live inside single-celled organisms more than a billion years ago. As such, mitochondria have their own DNA (see next paragraph), which contains 13 coding genes with about 16,000 base pairs. Thus, a given cell in your body contains both the nuclear DNA and mitochondria and their DNA.

What is interesting is that generally mitochondrial DNA (mtDNA) is inherited only from the mother, clearly a violation of Mendelian inheritance. Because mtDNA does not recombine sections of DNA from the mother and father, it is very stable and mutates slowly. This gives mtDNA a special application in the study of evolution. It has helped researchers to discover the genetic link in certain disorders that show maternal or mitochondrial inheritance patterns, such as Leber’s hereditary optic neuropathy, a disorder that results in rapid loss of vision beginning in adolescence.

Evidence is also accumulating that mitochondrial dysfunction is involved in specific mental disorders (Fanibunda & Vaidya, 2021; Regenold et al., 2009; Rossignol & Frye, 2012). This is referred to as the mitochondrial dysfunction hypothesis. Mitochondrial dysfunction has been identified using a number of different techniques. One technique is to identify structural changes in mitochondria. A second is to examine the manner in which the mitochondrially related genes produce proteins. A third is the use of metabolic studies. Since mitochondria are involved with energy production, it is possible to measure glucose concentration in cerebrospinal fluid. These studies have shown differences in mitochondrial functioning in individuals with bipolar disorder, schizophrenia, and autism spectrum disorders as compared to healthy controls.

What Are Endophenotypes?

In a move to go beyond using only the signs and symptoms of psychopathology, there has been a search for stable internal physiological or psychological markers that underlie a disorder (Bigdeli & Harvey, 2021; Correa-Ghisays et al., 2022; Gottesman & Hanson, 2005; Gottesman & Shields, 1972; Insel & Cuthbert, 2009; Miller & Rockstroh, 2013). Such markers have been called endophenotypes. Endophenotypes are patterns of processes that lie between the gene (the genotype) and the manifestations of the gene in the external environment (the phenotype). Unlike symptoms that can be observed, endophenotypes cannot be seen except with special equipment and computational analysis, such as brain imaging procedures or patterns of performance on neuropsychological tests. For example, individuals with a given disorder may show certain types of electroencephalogram (EEG) responses to particular stimuli or a certain pattern of brain activity that is different from that seen in healthy individuals. Those with autism have been shown to have fewer connections between brain areas than siblings or controls, and this is seen as an endophenotype (Moseley et al., 2015).

Like genes, the presence of the endophenotype does not necessarily mean that the disorder itself will be present. For example, a specific endophenotype may be seen in both a person with schizophrenia and their first-degree relatives, although the relatives themselves do not have schizophrenia. As such, an endophenotype can help to identify the systems involved in a particular disorder as well as note which genes are influenced by environmental and other internal factors related to a disorder. The potential of endophenotypes is their ability to better articulate the relationship between genetic and environmental factors in the development of psychopathology and to clarify which processes are influenced. In Chapter 4, you will learn about a National Institute of Mental Health (NIMH)–supported diagnostic approach based on endophenotypes, the Research Domain Criteria (RDoC).

Current Thinking on Genetics and Psychopathology

As our understanding of the genetic and environmental factors that contribute to mental illness has become more complex, research has begun to target particular processes related to psychopathology. For example, there exists a gene (SERT) that is involved in the removal of the neurotransmitter serotonin from the synapse. A variant of the SERT gene has been associated with depression, alcoholism, eating disorders, ADHD, and autism (Serretti et al., 2006). Likewise, a variant of the gene DßH, which is associated with the synthesis of norepinephrine from dopamine, is associated with schizophrenia, cocaine-induced paranoia, depression, ADHD, and alcoholism (Cubells & Zabetian, 2004). It is suggested that the lower level of the proteins produced by the DßH gene is associated with a vulnerability to psychotic symptoms.

As researchers discover genes related to specific forms of mental illness, there may be a need to reorganize how we view mental illness. One study analyzed the genes from 33,332 individuals with a mental disorder in comparison with 27,888 without a disorder (Cross-Disorder Group of the Psychiatric Genomics Consortium et al., 2013). This research suggests that similar genetic risk factors involved in calcium channel signaling exist for what we have considered to be five separate disorders: autism spectrum disorder, schizophrenia, bipolar disorder, major depressive disorder, and ADHD. This study implies that a particular genetic makeup may put some individuals at higher risk for developing a variety of disorders. There is also research that suggests that having certain mental disorders, such as schizophrenia, may actually protect these individuals from getting certain types of cancer (Tabarés-Seisdedos & Rubenstein, 2013).

More recently, as the cost of performing genotyping has been reduced, it has become possible to obtain a more complete analysis of an individual’s genome (Friedman et al., 2021; Plomin, 2018). Studies based on this rich data are referred to as genome-wide association studies (GWASs). These studies typically use the genetic data from a large number of individuals to statistically determine genetic differences associated with a particular trait, such as personality factors, or a particular mental disorder, such as depression, eating disorders, PTSD, addiction, and so forth. Some studies use data from as many as 100,000 individuals. Currently, over 800 researchers from 40 countries share genomic data from over 400,000 individuals (see For Further Reading for a description of this work).

One interesting GWAS showed that mental disorders show less genetic variation across disorders, whereas neurological disorders such as Parkinson’s disease, epilepsy, Alzheimer’s disease, and multiple sclerosis show a unique set of genes associated with each disorder (The Brainstorm Consortium, 2018). We will refer to GWASs when appropriate throughout this book. GWASs also offer an alternative to the traditional twin studies (Friedman et al., 2021).

In GWASs that examine the effects of many genes on psychological processes (Breen et al., 2016; Giangrande et al., 2022), researchers go through hundreds or thousands of changes in DNA called single-nucleotide polymorphisms (SNPs, pronounced “snip”). Each of us has about 4 million SNPs, but we all do not have the same 4 million. As shown in Figure 2.25, the task is to find similar SNPs in those with a particular disorder as compared to a control group. These studies have been applied to psychological disorders and involve a number of researchers from over 40 countries (Breen et al., 2016; Sullivan et al., 2018)

The logic of performing a GWAS is to begin with the trait or disorder that one wants to study. The focus is then on the genetic structure related to a specific trait or disorder. Genetic differences seen in even a large number of individuals can be very small. Thus, what one needs to do is to statistically determine which genetic properties are correlated with the trait under study from the large number of individuals. The result of this type of correlation procedure is referred to as a polygenic score. The actual procedure is more complicated than this and uses a structural equation model. However, the basic idea is to determine how well a polygenic score derived from a GWAS is able to predict individual differences (Friedman et al., 2021; Plomin, 2018).

There are multiple current approaches to GWASs. One approach is to examine specific networks of the brain, such as executive, default, and salience networks, in terms of common genetic variants influencing these processes (Zhao et al., 2022). Further research studies have begun to examine networks of genes in the brain as reflected in their co-expression (Hartl et al., 2021; Yates, 2021). Gene co-expression analysis is a data analysis technique that helps identify groups of genes with similar expression patterns across several different conditions (Montenegro, 2022). Mental disorders disrupt a variety of cognitive, emotional, and motor processes that develop over a person’s lifetime and are guided by thousands of genes (see Plomin, 2018, for an overview).

In addition, research has also shown rare variants of a small number of genes that can have a large effect (Gibson, 2012; Singh et al., 2022). For example, one study showed that 10 rare variants of some genes are associated with substantial risk for schizophrenia (Singh et al., 2022). Likewise, very rare variants of specific genes are associated with bipolar disorder (Palmer et al., 2022). Overall, disorders such as schizophrenia are related to both hundreds of genes, each of which has a common influence, and to a small number of rare variants of a gene, each of which has a large effect (Iyegbe & O’Reilly, 2022).

Traditional genetic research suggests a complicated relationship between genetic conditions and environmental factors. For example, the MAOA gene, which is located on the X chromosome, makes the neurotransmitters serotonin, norepinephrine, and dopamine inactive and is associated with aggression in mice and humans. Caspi and his colleagues (2002) performed a longitudinal study and found that mistreatment as a child influenced some boys differently from others later in adulthood. Those boys who were mistreated in childhood and had a particular form of the MAOA gene were more likely to be violent and engage in a variety of antisocial behaviors as adults, as well as have problems with law enforcement officials. Those without this particular form of the gene did not display antisocial behaviors, even if they had been mistreated as children. Thus, environmental influences in terms of maltreatment modulate the expression of specific genetic structures but not the expression of others.

Thus far, we have considered brain changes and genes turning off and on. These events are typically short term and can change quickly. Moving to the evolutionary perspective, we will look at a longer time frame in which environmental factors influence the genes that are passed on to the next generation. Let’s begin with the major themes of evolution and then consider psychopathology from an evolutionary perspective.

The Themes of Evolution

One of the main themes of evolution is the manner in which organisms are in close connection with their environment. It is this close connection that allows for change to take place, including the turning on and off of genetic processes. In humans, there is another layer of complexity involved in the process. Part of this complexity comes from the fact that humans are born less fully developed at birth than many other species and thus are sensitive to changes in their environment as they continue to develop. This includes our relationships with our family and others with whom we initially come in contact. As humans, we also develop societal and cultural perspectives. These perspectives become the backdrop of our environment. Unlike animals that live within nature, we as humans largely live within the backdrop of our culture. Thus, we are influenced by our culture and pay close attention to it.

Another part of our complexity as humans is our ability to reflect on ourselves and our world. In this way, a layer of thought can be injected between the person and the environment. This allows for expectation and imagination to play a role in human behavior and experience. Some have even suggested that humans may be the only species to imagine the world and themselves differently from how they appear. In this sense, our inner world of thoughts and feelings becomes another environment in which we live. For example, you can tell yourself you are wonderful or you are stupid, and there is no one inside you to dispute this. One positive aspect of this is that your inner world allows you to plan future actions and reflect on past ones, but it can also be experienced as distress when your internal thoughts reflect such states as anxiety or hopelessness. Our internal thoughts at times may lead to interpretations of the environment or ourselves that may not be productive. This adaptive human ability to reflect, which should lead to successful survival, sexuality, and social relations, sometimes leads instead to interactions that reduce the close connection between the individual and their internal and external environment. As we will see, this lack of connectedness lies at the heart of psychopathology.

As noted in Chapter 1, humans not only consider themselves but also consider others. A positive side of this is the ability to understand the internal experiences of another. This allows us to experience empathy. We can also consider how we appear to others and other questions of self-image. One aspect of this is related to sexual processes. That is, we can say or do things that make us more attractive to a potential mate. In terms of self-preservation, humans also have a personal history that allows each individual to learn from the past and develop strategies for living. These strategies tend to protect us and may even have saved our lives in exceptional cases. However, it is also possible for the strategies that work in one environmental situation not to work in another. When a person loses contact with the current environment and applies strategies that worked perhaps in an earlier time, then unsuccessful adaptation is the result.

This lack of connectedness to our environment may take place on both an external and an internal level. On an external level, the person finds herself different from the group or even seeks to be separate from others. This is not our historical experience, since individual humans have never lived in isolation. As a species, we have always lived in close contact with other humans, which has led to the development of societies and cultures. In fact, many of the specific abilities of humans are geared to social interactions on a variety of levels. When they no longer have the connection with the group, many individuals experience a sense of loss. This loss typically carries with it the experience of negative affect and depression and often a need to withdraw from contact with others and even themselves. On an internal level, humans frequently have the need to explain to themselves the events that have just occurred, which may include anger, distorted perceptions, or a genuine plan for recovery. The extreme cases we refer to as psychopathology.

Psychopathology From an Evolutionary Perspective

Psychopathology from an evolutionary perspective goes beyond the traditional psychological and physiological considerations. Considering the evolutionary perspective, we ask additional questions. One question might be, how long in terms of our human history has a particular psychopathological disorder existed? As noted in Chapter 1, a WHO study examined the presence of schizophrenia in a number of countries with very different racial and cultural backgrounds (Sartorius et al., 1986). What these authors found was that despite the different cultural and racial backgrounds surveyed, the experience of schizophrenia was remarkably similar across countries. Likewise, the risk of developing schizophrenia was similar in terms of total population presence (about 1%). Further, the disorder had a similar time course in its occurrence, with its characteristics first being seen in young adults.

If you put these facts together, they suggest that schizophrenia is a disorder that has always been part of the human experience. Because it is found throughout the world in strikingly similar ways, this suggests that it existed before humans migrated out of Africa. The genes related to schizophrenia were carried by early humans who migrated from Africa, and thus, its presence is equally likely throughout the world. Given these estimates as to the history of the disorder, one might ask why schizophrenia continues to exist. We know, for example, that individuals with schizophrenia tend to have fewer children than individuals without the disorder. Fewer children with these genes would over time lead to even fewer children with the genes. Thus, we might assume that schizophrenia would have disappeared over evolutionary time in that it reduces reproductive success and has a genetic component. However, this is not the case.

This creates a mystery for evolutionary psychologists to solve. To answer this question, we can draw on many considerations. Perhaps, in the same way that sickle-cell anemia is associated with a protection against malaria, schizophrenia protects the person from another disorder. Or, perhaps like the reaction of rats to stress, which results in depression-like symptoms, the symptoms seen in schizophrenia are the result of a long chain of stressful events in which the organism breaks down in its ability to function. Psychopathology could even go in a more positive direction and be associated with creative and nontraditional views of the world. For example, there are a number of accounts that have noted greater creativity in families of individuals with schizophrenia.

The evolutionary perspective helps us ask such questions as what function a disorder might serve as well as how it came about. In the same way that pain can be seen as a warning system to the body to protect it from tissue damage, anxiety may have evolved to protect the person from other types of potential threats. For example, many of the outward expressions of social anxiety parallel what is seen in dominance interactions in primates. Submissive monkeys avoid contact with most dominant ones in much the way that human individuals experiencing social anxiety avoid dominant members of their group. This suggests the possibility that anxiety may have its evolutionary origins in dominance structures. If this were the case, then we might expect to see some relationship to sexual instinctual processes, as is the case with dominance. The evolutionary perspective also helps us think about what might be solutions to how psychopathology should be treated. As touched on in Chapter 1, these are some of the questions that will be discussed in this book.

One perspective of the evolutionary approach has been to redirect psychology back to the basic processes of human existence such as survival, sexual processes, and social behavior. We can then ask what types of disorders are found within each broad category. We can also consider the developmental and social processes and ask how these processes may be involved in psychopathology. Thinking in these terms, we may come to discover that disorders that have very similar end states may have developed from distinct beginning conditions. Depression, for example, can result from extreme stress that brings forth self-preservation instincts. Depression can also result from the loss of significant people in one’s life. Further, loss of social status is also associated with depression. Thus, what appear to be similar symptoms may have been produced by separate and distinct trajectories.

Another psychopathology that has been approached from an evolutionary perspective is the category of personality disorders. Personality disorders reflect a rigid approach to dealing with social relationships. Two commonly discussed personality disorders are antisocial personal disorder (also known as psychopathic personality) and histrionic personality disorder. Psychopaths are described as manipulative, callous, dishonest, and self-centered. They are antisocial in the sense that they display no need to follow the traditional rules of a society and little remorse or guilt for their actions. For example, they would contract and collect money for a job they had no intention of doing. They would clearly qualify as those whom evolutionary psychologists refer to as cheaters. On the other hand, individuals with a histrionic personality disorder overly seek the attention of others and are very emotional in their reactions. They can be manipulative in their interpersonal relationships.

Harpending and Sobus (1987) suggested that the psychopathic and the histrionic personality styles represent different adaptive strategies in relation to sexuality. Both of these personality types were viewed by Harpending and Sobus as cheaters. Given that it is more common to see men with antisocial personality disorder and women with histrionic personality disorder, these researchers suggest that this results from different reproductive strategies. A man cheating in a sexual relationship should be able to persuade a woman to copulate with him while deceiving her about his commitment to her and his willingness to offer resources for the offspring. A cheating woman, on the other hand, would exaggerate her need for the man and make herself appear helpless and in need so that he would give her additional attention and resources. She would also be willing to put her own needs ahead of those of her offspring even to the extent of abandoning them. The work of Harpending and Sobus shows how evolutionary thinking can help to explain possible motivational factors of a particular disorder as well as the demonstrated gender differences.

Let’s look at another well-studied process—sleep—as a model for thinking about psychopathology. Since sleep disturbance is often associated with a variety of psychopathological disorders, this will let us consider how normal processes may be influenced to appear pathological. Most people would like to go to sleep when they want to and not be awakened during the night. However, evolution is not always about what makes us feel good. The critical question from an evolutionary perspective is what function sleep plays. In considering this question, we can look at sleep as a model for how we might approach other basic psychological processes.

One initial question to ask is this: Has sleep been shaped by natural selection? Some researchers answer yes to this question (Nesse & Williams, 1994). They offer at least five reasons for why this is so. First, sleep is found in a variety of organisms and is perhaps universal among vertebrates. However, not all animals sleep in the same way. Elephants and cows spend most of their sleep time standing up. Dolphins sleep with one half of their brain, while the other half remains awake. Second, all vertebrates share similar mechanisms that control sleep and dreaming. These mechanisms are found in the more primitive areas of the brain. Third, the pattern of sleep seen in mammals with periods of rapid eye movement and faster EEG activity within the sleep period is also seen in birds. Since the evolution of birds went down a different pathway before the time of dinosaurs, this suggests that sleep is a very primitive and basic mechanism. Fourth, in examining the sleep patterns across species, there appears to be support for the idea that these patterns adapted to match the ecological niche of that particular animal. Fifth and finally, all animals show deficits in response to a lack of sleep. Currently, a variety of researchers are seeking to determine the function of sleep. The best evidence suggests that it allows for restoration of certain physiological processes. There is also evidence that sleep consolidates information learned during waking hours. One conceptual idea is that, given the light–dark cycle produced by the earth’s rotation around the sun, sleep developed as a protective mechanism since it is more dangerous to be out alone at night.

In summary, we can ask critical questions concerning psychopathology that relate to other evolutionary processes:

We can ask if the experience of mental illness is universal. If it were not universal, then it would be difficult to argue that we should study psychopathology from an evolutionary perspective. If it is a universal process such as emotionality or language, then we can begin to ask about the nature of mental illness and how its existence fits into our history as humans.

We can ask if there is an adaptive value to the behaviors and experiences displayed in psychopathology. It is easy to see that there is a value in not trusting what someone tells you some of the time, but is there any adaptive value in not trusting what anyone tells you all of the time or to think that everyone is always out to get you?

We can look for evidence of psychopathology across human history. This includes the question of whether we see signs of psychopathology in nonhuman species.

We can seek to understand the nature of psychopathology. That is to say, should we consider psychopathology to be qualitatively different from normal functioning, or is it the situation in which normal processes have been taken to the extreme? We know, for example, that allergic reactions are situations in which our immune system is overreactive. We also know that fever is the process by which body temperature is raised to fight infection. However, the fever uses energy and can damage the body.

We can ask if it is protective in some manner. Like carrying the trait for sickle-cell anemia, does having schizophrenia or depression, for example, make you less likely to experience another disorder?

We can ask if psychopathology is a recent process. That is, should we consider psychopathology as the result of a mental system that evolved millennia ago and is interacting with a high-paced modern environment? For example, aggression in teenagers involved in gangs may reflect behaviors that were adaptive in previous times but are no longer adaptive for society today.

These questions are not mutually exclusive. As you will see, they also represent some of the ways scientists and others have sought to understand psychopathology. From an evolutionary perspective, the study of psychopathology begins with the three instincts of survival, sexuality, and socialness. From this perspective, psychopathology becomes a disturbance of these instinctual processes. Throughout this text, considerations of how certain evolutionary processes might contribute to psychological disorders will be discussed.

The basic element of the brain is the neuron that is connected to other neurons. Since the human brain has been estimated to contain 86 billion neurons and more than 100,000 kilometers of interconnections, scientists have analyzed them in the context of networks. Three specific networks have been examined relating to psychopathology—the default network (also called the intrinsic network), the central executive network, and the salience network. Psychopathological disorders have been shown to have problems in turning networks on or off as well as problems in the connections within the network itself.

Scientists have been able to use the manner in which neurons work as a window into their function. A variety of techniques for observing activity in the brain have been developed. Currently, the major types of brain imaging techniques are EEG, MEG, PET, and fMRI. There are a number of trade-offs that researchers and clinicians must consider when choosing a brain imaging technique. It begins with the research or clinical question one is asking, which determines whether the appropriate measure is one of structure (spatial resolution) or how fast a process can be measured (temporal resolution). With the opening of this window into individuals’ internal processes, the new field of neuroethics has started asking questions concerning who should have access to that information.

Genes form the blueprint that determines what an organism is to become. They are found on chromosomes in every cell of the body. Within each gene, DNA (the information storage molecule) transfers information to RNA (the information transfer molecule) to produce a particular protein. The location of the genes in the body makes a difference in that cells in the brain produce different proteins from those in the muscles, or liver, or heart. A gene is turned on (produces the protein) or turned off (does not produce the protein) relative to specific events.

The basis of evolution is genetic variations that occur in response to the environment and that can be inherited and passed on to future generations. The study of genetics began in the 1800s with the work of Gregor Mendel, who established the initial principles of genetic inheritance. Subsequent research has added complexity to that initial conceptualization. Mitochondrial inheritance, for example, has been found to involve the mtDNA that generally is inherited only from the mother. Epigenetic inheritance is based on the fact that the processes that determine which genes turn on and off can be passed on to the next generation. Thus, although DNA itself cannot be influenced by the environment, it is possible for the environment to influence future generations through its changes to those processes that turn genes on and off. Given this complexity, it is no wonder the original hope of finding a few genes that were involved in particular mental disorders has not panned out. Currently, one promising focus of research has been to identify endophenotypes—patterns of processes lying between the gene (the genotype) and the manifestations of the gene in the external environment (the phenotype)—for particular psychological disorders.

One of the main themes of evolution is the manner in which organisms are in close connection with their environment. It is this close connection that allows for change to take place, including the turning on and off of genetic processes. In humans, there is another layer of complexity involved in the process. Part of this complexity comes from the fact that humans are born less fully developed at birth than many other species and thus are sensitive to changes in their environment as they continue to develop. Unlike animals that live within nature, we as humans largely live within the backdrop of our culture. Another part of our complexity as humans is our ability to reflect on ourselves and our world. In this way, a layer of thought can be injected between the person and the environment. This allows for expectation and imagination to play a role in human behavior and experience. This lack of connectedness to our environment may take place on both an external and an internal level.

From an evolutionary perspective, the study of psychopathology begins with the three instincts of survival, sexuality, and socialness. From this perspective, psychopathology becomes a disturbance of these instinctual processes. The evolutionary perspective goes beyond the traditional psychological and physiological considerations and asks some critical questions concerning psychopathology. First, is the experience of mental illness universal? Second, is there an adaptive value to the behaviors and experiences displayed in psychopathology? Third, can we see evidence of psychopathology across human history as well as in nonhuman species? Fourth, what is the nature of psychopathology—is it qualitatively different from normal functioning, or have normal processes been taken to the extreme? Fifth, is psychopathology protective in some manner? Sixth, is psychopathology a recent process—a result of a mental system designed in prehistory interacting with a thoroughly modern environment?

Study Resources

Review Questions

What are genotypes, phenotypes, and endophenotypes? How are these three concepts used in understanding the development of psychopathology?

This chapter states that there is a complicated relationship between genetic conditions and environmental factors. How are these two concepts involved in the development and maintenance of psychopathology? How is it made even more complex by epigenetic processes?

How have the discoveries of epigenetic inheritance and mitochondrial inheritance enriched our understanding and added to the complexity of Mendel’s initial theory of genetic inheritance?

How does the small world framework from social science help us understand how neurons are connected in a network? What implications does this have for the transmission of information within a network and across networks?

Historically, those interested in neuroscience research have focused more on the universality of human processing than on the diversity found in different cultures. What evidence can you present to show that culture creates diversity in human psychological processing?

CHAPTER 4

If you are a clinician, people come to see you in a variety of ways. Some people set up an appointment and tell you about how they are feeling distressed. They may tell you about feeling anxious or sad. If you work in a hospital, people may be brought to you by others who are concerned by the behaviors these patients display or the experiences they describe. As a clinician, your job is to make sense of the information you are given. The first task is that of assessment.

Psychological assessment is simply the process of gathering information about a person so that you can make a clinical decision about that person’s symptoms. In the process, you may create a variety of hypotheses about the possible causes of the symptoms. Had the person taken drugs that were causing the behavior? Did the person suffer a negative experience such as being robbed or raped? Is the behavior part of an underlying physical or mental disorder? Part of the task of the clinical assessment is to gather data necessary to rule out or support the possible causes of the symptoms.

The Clinical Interview

Most mental health professionals use a clinical interview to initially gather information concerning the status of an individual with whom they are working. Since the interview is also an interaction between two people, it is a chance for the professional to establish rapport, which will lead to more complete information. The information gained from this interview includes not only the individual’s present symptoms but also the social and cultural context in which these symptoms appear. This context includes the individual’s social support, family relationships, and connections within their community. It is also important to assess the individual’s attitudes, emotions, and experiences of others in their world. The clinical interview further offers the opportunity to assess the individual’s current ability to maintain their own health and well-being.

Overall, the major areas of consideration in a clinical interview are (a) the current areas of distress and their history; (b) any past mental health problems; (c) social history, including social support; (d) the manner in which cultural factors may influence the current condition; and (e5) any way in which previous family, medical, or psychological factors may influence the current situation.

The Mental Status Exam

Throughout the world, the clinical interview has been organized into major categories and is referred to as the mental status exam. This exam is often given quickly to gain initial information of both an objective and a subjective nature.

The first major category of the exam is the individual’s appearance and behavior. In the report, the mental health professional would note such factors as the individual’s clothing, grooming, and posture. Motor activity, such as slow movements, may be part of a later diagnosis of depression, whereas quick, abrupt movements may be associated with mania.

The second major category of the exam is mood and affect. Affect refers to the emotions that the individual is expressing during the interview. The person might seem happy or sad. The professional might note that the person laughs or cries in describing situations, where other individuals would not laugh or cry. Such affect would be described as inappropriate. It should also be noted if the individual shows no affect when describing situations where others would be happy or sad, such as receiving a large raise in pay or losing a friend. Such affect is said to be flat. Mood, as compared with present affect, is more long term. To assess this, the professional notes how the individual has been feeling recently. For example, has the individual been feeling blue or angry?

The next category is speech quality. Here, the professional notes the manner in which an individual speaks. Is the person speaking quickly or very slowly? Does the person’s manner of speaking feel pressured? Does the person speak very quietly or with great volume? These are the types of speech characteristics the professional can observe and record.

The next major category is thought processes. In describing thought processes, the professional can note if the individual answers the questions that are asked and adds more information when appropriate. On the other hand, some individuals will produce responses that are not related to the question asked or tell a narrative in which each sentence is not related to the one that came before it. This is referred to as a flight of ideas. The content of the individual’s thought is also important. Is there a theme to the thoughts, such as that the CIA is out to get the individual? This would be referred to as delusional thinking. Does the individual keep repeating a certain theme? For example, some individuals express constant concern that they will have a heart attack or that their spouse is cheating on them. This is referred to as obsessional thinking. The professional should also take particular note if the person is talking about suicide or homicide. This may require an intervention.

Another major category is perceptions and a general awareness of one’s surroundings. Distorted perceptions can include hallucinations, in which the individual perceives experiences without external stimulation. Individuals with a psychotic disorder may hear a radio program talking to them directly or respond to voices in their head. General awareness of one’s surroundings includes the question of whether the person knows who and where they are and the present date and time.

The final categories describe intellectual functioning and insight. Intellectual functioning is generally noted in terms of current vocabulary used in the interview as well as previous academic achievement. The professional can also note if the person has an abstract understanding of the information they are reporting. Insight refers to the individual’s awareness of their own self and the factors related to their current situation and distress.

A structured interview is an evaluation technique that is tightly systematized in terms of the questions asked. The idea is that by asking clients the same set of questions, it is possible to have better consistency across interviewers. Likewise, because every client receives the same questions, it is assumed that there will be more consistency across clients.

Structured Clinical Interview for DSM Disorders

The current classification manual used by most clinicians in North America is the Diagnostic and Statistical Manual of Mental Disorders (5th ed., text rev.; DSM-5-TR) (American Psychiatric Association [APA], 2022). The DSM will be discussed in some detail later in this chapter. Based on the DSM-5-TR, with its specific criteria for each category of psychological disorder, it is possible to ask questions in an interview that directly probe for the existence of these criteria. The Structured Clinical Interview for DSM Disorders (SCID) sets forth these questions along with a decision tree for directing follow-up questions. For example, if you want to determine if a person displays an obsessive–compulsive disorder, you would begin with a general question concerning whether the individual experiences thoughts that keep recurring. If the person says yes, you would then ask what those thoughts were. The decision tree would help you to determine if the individual conceived of these thoughts as something produced in their own mind or imposed on the person by an outside agent. Thoughts experienced as not from oneself would be more characteristic of a psychotic disorder, whereas those recognized as coming from one’s own mind might indicate a possible obsessive–compulsive disorder. Individuals with anxiety may also experience worries as thoughts coming into their mind, and the SCID would help to determine whether the person experiences obsessive–compulsive disorder or anxiety. The next set of questions would help the professional determine whether compulsions were also present. The SCID would instruct the interviewer to ask if there is anything the person has to do over and over again, such as constant hand washing or checking a door lock several times.

Assessing Cultural Dimensions

Over the past 40 years, mental health professionals have become increasingly aware that mental illness takes place within the context of a particular culture (Henderson et al., 2016; Marsella & Yamada, 2007). Initially, there was a realization that specific disorders, such as depression, schizophrenia, and stress-related disorders, are understood differently in different cultures (Draguns, 1973; Draguns & Tanaka-Matsumi, 2003). That is to say, a fuller understanding of mental illness requires an understanding of cultural context. Although every culture has words for severe mental illness (e.g., psychosis) and mood disorders (e.g., depression and anxiety), cultures vary in what they commonly consider normal and deviant. Cultural LENS: Empirically Supported Research Approaches and Cultural Competence notes that culture not only informs how individuals view their own distress but also influences how that distress is expressed.

With DSM-5, a Cultural Formulation Interview (CFI) has been developed to help mental health professionals obtain information concerning the person’s culture. (This has been updated in DSM-5-TR.) In general, the CFI focuses on five domains:

Cultural identity of the individual—This domain in DSM-5-TR describes how the individual sees themself in terms of ethnic, racial, or cultural identity. It can also include how connected the person is with their culture of origin. For migrants, this includes the individual’s connections to both their place of origin and their new home.

Cultural conceptualizations of distress—This domain refers to how the person’s culture would influence their experience of the disorder. For example, different types of symptoms might be more acceptable in one culture than another. Also, some individuals may be less willing to seek help and unwilling to describe the experiences they are having in certain aspects of their lives.

Psychosocial stressors and cultural features of vulnerability—Psychological concerns, as noted in Cultural LENS: Empirically Supported Research Approaches and Cultural Competence, vary by culture. Likewise, the amount of support offered by the family and community also vary. In conducting an interview, the mental health professional needs to obtain an overall picture of the individual’s social environment, including religion, family, and social networks. An emphasis on how cultural elements affect the presentation of a particular distress or disorder must be considered.

Cultural features of the relationship between the individual and the clinician—This domain emphasizes how the relationship between an individual and a mental health professional can be influenced by cultural factors. If a person has experienced negative situations with authority figures in the world outside of the interview, this could influence how the person relates to the mental health professional. Likewise, if the culture places a high regard on health professionals, then the person may not correct or interrupt with additional information during the interview. This domain would also include how the person expects to be treated by the mental health professional and expectations for future treatment.

Overall cultural assessment—This domain represents an overall assessment and implications of what was identified in the previous domains. Treatment preferences can be described that may be incorporated into the treatment plan.

Understanding the cultural context of a disorder helps increase the validity of the assessment and diagnosis procedure. The CFI asks 16 questions related to culture indirectly. For example, the mental health professional would ask the person how their family, friends, or community view what is causing the problems. In this manner, people can describe their understanding of their problems with a direct or indirect reference to their culture.

Reliability and Validity in Relation to Psychopathology

Concerns about the accuracy of assessment and classification of psychopathology require us to consider two very different questions. The first has to do with the person who is being interviewed. We need to know if the person is giving us accurate information. Sometimes, individuals will “fake bad” if there is some advantage, such as receiving a larger disability payout. Other times, individuals will “fake good” and deny there are any problems.

The second question is which assessment instruments to use. An assessment instrument can be an interview, an inventory, a mood scale, or other type. In considering instruments, we think about measurement. Measurement considerations help to define the variety of instruments that we use and the theoretical variables that these reflect.

Traditionally, the two key measurement issues are reliability and validity. That is, does an instrument measure the construct consistently (reliability) and accurately (validity)? The measurement of temperature, for example, is based on the kinetic theory of heat, which helped define the type of devices used. With psychopathology, however, we lack formal definitions that tell us exactly how to make measurements. In fact, we are both trying to learn about disorders and creating techniques for making diagnoses. This makes reliability and validity considerations both more difficult and more important.

Reliability

Reliability asks the question of whether the instrument is consistent. We would expect, for example, that the odometer in our car would reflect that we drove a mile each time we drove 5,280 feet. We would also expect our bathroom scale to show the same reading each time we step on it if our weight had not changed. Researchers interested in questions of measurement discuss a number of types of reliability:

Internal reliability—Internal reliability assesses whether different questions on an instrument relate to one another. If we were seeking a general measure of depression, for example, we would want to use questions that relate to one another. Questions related to feeling sad, not having energy, and wanting to stay in bed would be expected to show internal reliability.

Test–retest reliability—Test–retest reliability determines whether two measurement opportunities result in similar scores. A key consideration with test–retest reliability is the nature of the underlying construct. Constructs seen as stable, such as intelligence or hypnotizability, would be expected to show similar scores if the same instrument was given on more than one occasion. In psychopathological research, measures of long-term depression or trait anxiety would be expected to show a higher index of test–retest reliability than measures that reflect momentary feelings of mood.

Alternate-form reliability—As the name implies, alternate-form reliability asks whether different forms of an instrument give similar results. If you were giving an IQ test, for example, you would not want to ask the same questions each time, since the individual could learn the answers from taking the test. Thus, it would be important to create alternate forms that reflect the same underlying construct.

Inter-rater reliability—Inter-rater reliability asks how similar two or more individuals are when they observe and rate specific behaviors. Psychopathology researchers often rate the emotional responses of children as they engage in various activities. An index of inter-rater reliability would measure how consistent different observers are in rating the same situation. Historically, one of the motivating factors for developing the DSM classification system was the discovery that different clinicians in different locations watched a film of a person with a mental health disorder and diagnosed it in different ways.

Assessment Validity

Validity, as described in Chapter 3, asks whether the instrument we are using is accurate. A clock, for example, could be reliable if it was always 5 minutes fast, but it would not be accurate. Unlike time, for which there is a definition in terms of atomic clocks, psychopathological disorders lack exact unchanging definitions. Although measures such as neuropsychological tests, brain images, and molecular and genetic changes suggest possible variables to be considered, there is currently no exact measure by which to diagnose psychopathology. This makes validity an important but complex concept. Partly for this reason, we consider a number of types of validity.

Content validity—the degree to which an instrument measures all aspects of the phenomenon. If a final exam only had questions from 1 week of the course, it would not be representative of what the students had learned. A variety of psychopathological disorders, such as depression, for example, have cognitive, emotional, and motor components. A measure that just asks if a person felt negative about the future would be seen as a less useful measure of depression than one that also asks about feeling sad and thoughts about suicide and self-worth.

Predictive validity—the degree to which an instrument can predict cognitions, emotions, or actions that a person will experience in the future. If an IQ test in high school predicted college performance, then it would be seen to have predictive validity. Many medical tests such as cholesterol measurements are designed to predict who is at risk for later medical conditions such as cardiovascular problems.

Concurrent validity—the ability of an instrument to show similar results to other established measures of the construct.

Construct validity—the extent that an instrument measures what it was designed to measure (Cronbach & Meehl, 1955). If a test was designed to measure what students learned in a course, then it would be a problem if the test was also sensitive to other factors such as intelligence or the ability to understand test questions asked in terms of double negatives.

Ecological validity—the manner in which data collected have been considered beyond the local context. For example, considering which cultural factors could be influencing the information obtained would improve the ecological validity of the data. This would also hold true in research studies involving mental illness in different cultures. That is, the meaning of a concept in one culture may be different from that in another.

This section considers different ways of assessing signs and symbols. These range from simply asking a person about their symptoms to comparing the person to others who have a similar disorder. Specifically, symptom and mood subtests such as the Beck Depression Inventory, personality inventories that are based on psychometric formulations such as the Minnesota Multiphasic Personality Inventory, projective techniques such as the Rorschach inkblot test and the Thematic Apperception Test, neuropsychological approaches such as intelligence tests, and neuroscience approaches demonstrate the variety of assessment measures.

Symptom Questionnaires

At times, it is important to know what a person’s symptoms are and how that person may compare with others in terms of reporting these symptoms. A variety of questionnaires have been developed that focus on particular sets of symptoms such as those associated with pain, sleep disorders, anxiety, and depression.

The Beck Depression Inventory (BDI) has been used in both clinical and research settings to assess symptoms associated with the experience of depression (Beck & Beck, 1972). The BDI has 21 items, each of which is presented in a four-choice format where the individual is asked to indicate which choice best fits their current experience. Here is an example:

I am not particularly discouraged about the future.

I feel discouraged about the future.

I feel I have nothing to look forward to.

I feel the future is hopeless and that things cannot improve.

A questionnaire such as the BDI is useful for determining the level of depressive symptoms that a person is reporting. Given that the measure has been in use for more than 40 years, there is considerable clinical and research data available in terms of level of depressive severity. The measure is also useful for noting changes in depression level during various types of treatment. During psychotherapy, for example, the measure could be given weekly to document changes in depressive experiences. A newer version of the scale (BDI-II) was developed in 1996 in response to the publication of DSM-IV, which changed a number of the diagnostic criteria for depression.

Personality Tests

For at least the past 2,000 years, there has been an understanding that individuals have particular styles for relating to the world and others. At the beginning of the 20th century, the personality styles of introversion and extraversion were studied. There was also an effort to examine the relationship between personality styles and psychopathology. A number of questionnaires have been developed to this end. One of the best known of these questionnaires is the Minnesota Multiphasic Personality Inventory (MMPI).

Minnesota Multiphasic Personality Inventory (MMPI)

The Minnesota Multiphasic Personality Inventory (MMPI) is an assessment measurement of personality traits that is composed of items of a true–false nature. The person taking the test simply indicates yes or no to statements such as “I have trouble falling asleep.” The test was developed in an interesting manner. The authors, S. R. Hathaway and J. C. McKinley, began with a large pool of items and then reduced these to 504 items that were determined to be independent of one another. They then gave these items to psychiatric inpatients at the University of Minnesota Hospital. These inpatients were further divided by diagnosis, and the responses of each group were compared with non-patients who had come to the hospital as visitors or relatives. The idea was to develop a scoring scheme that would differentiate those with mental disorders from those without. In this sense, the content of the item was less important than its ability to discriminate between those individuals with a specific disorder and those without the disorder, as well as between disorders.

The clinical scales in the original MMPI used the following categories:

Hypochondriasis (Hs)—Individuals who endorse these items show an excessive concern with bodily symptoms.

Depression (D)—Individuals who endorse these items display characteristics of depression, such as trouble sleeping, loss of appetite, feeling sad, suicidal thoughts, and loss of interest in positive events.

Hysteria (Hy)—Individuals who endorse these items tend to view and experience the world in an emotional manner. They may overdramatize their situation. They may also experience emotional difficulties through bodily symptoms such as headaches or upset stomach when in a difficult psychological situation.

Psychopathic deviate (Pd)—Individuals who endorse these items display antisocial tendencies and experience conflicts with their environment. They may also exploit others without remorse.

Masculinity–femininity (Mf)—These items reflect the degree to which an individual endorses the traditional gender roles of men or women.

Paranoia (Pa)—Individuals who endorse these items display suspiciousness of others. They also view the world in terms of “who is out to get them.”

Psychasthenia (Pt)—Individuals who endorse these items display excessive anxiety and obsessive behavior.

Schizophrenia (Sc)—Individuals who endorse these items display bizarre disorganized thoughts along with a lack of normal contact with reality, including social aloofness. Various sensory problems such as hallucinations may be present.

Hypomania (Ma)—Individuals who endorse these items experience high-energy states associated with poor judgment and impulse control.

Social introversion (Si)—These items reflect the extent to which an individual’s answers indicate social introversion and extraversion.1

By placing an individual’s responses to questions in each of the categories on a normal distribution graph, it is possible to see which categories deviate from responses seen in the general population. In addition to the clinical scales, the MMPI also contains validity scales. These scales were designed to determine whether the person is trying to skew the results by either “faking good” or “faking bad.” One type of item included in these scales is one that most healthy individuals would not agree to, such as “I have never told a lie.” This last item would be found on the lie or L scale. The infrequency or F scale is composed of items that are infrequently endorsed by the general population. Endorsing these items could come about because the person wanted to look as if they had psychological problems (“faking bad”). It could also be the case that the individual was confused or could not read or understand the items. The defensiveness, or K, scale seeks to identify individuals who deny having any psychological problems (“faking good”). The number of times the person responds with “can’t say” can be noted to help determine the validity of the MMPI. Further, as might be expected after more than 70 years of use, a variety of additional scales have been developed that have been used for both clinical and research purposes.

In 1989, a new version of the MMPI, the MMPI-2, was released, which improved the generalizability of the test. This was followed by the MMPI-2-RC, where RC stands for restructured clinical scales (Ben-Porath, 2012). The 10 scales of the original MMPI plus the validity scales were expanded into 51 scales based on psychometric and research considerations based on 433 items.

In 2020, MMPI-3 was released (Hall et al., 2022). Like the MMPI-2, the MMPI-3 was “normed” on a better representation of the general population in terms of race, age, sexual orientation, occupational level, income, and geographic location. The MMPI-3 has 355 items that are used to construct 10 validity and 42 descriptive scales. These scales are presented as a hierarchy. The three broad scales at the top are Emotional/Internalizing Dysfunction (EID), Thought Dysfunction (THD), and Behavioral/Externalizing Dysfunction (BXD). These are followed by eight clinical scales: Demoralization, Somatic Complaints, Low Positive Emotions, Antisocial Behavior, Ideas of Persecution, Dysfunctional Negative Emotions, Aberrant Experiences, and Hypomanic Activation. The final 26 specific problem scales include such problems as anxiety-related experience, stress/worry scale, suicidal/death ideation, helplessness/hopelessness, self-doubt, anger proneness, behavioral restricting fears, family problems, social avoidance, self-importance, and others’ problems.

Projective Tests

Projective instruments are assessment tests composed of ambiguous stimuli. They can range from seemingly random patterns such as an inkblot to ambiguous drawings of individuals or objects. The individual is asked to describe what the patterns look like, what they bring to mind, or what is being depicted in the drawing.

The basic idea of projective testing is based on the theoretical ideas of Sigmund Freud and others who sought to understand the dynamics of the mind. One important distinction Freud made was between types of thinking (Erdelyi, 1985; Westen et al., 2008). Primary process thought, which is seen in dreams or letting your mind wander, is not organized logically but in terms of associations between thoughts and feelings. Secondary process thought, on the other hand, is logically organized. Freud suggested that it was possible to understand the cognitive and emotional connections of a person’s mind in terms of primary process. Freud’s technique for exploring these connections was free association and dream analysis.

The basic technique of free association is to have a person lie on a couch and say whatever comes into their mind. Since the therapist sits behind the client, there is little in the environment for the client to react to. It is the therapist’s job to notice how a person’s thoughts and emotions are connected. During free association over a period of months, it is assumed that patterns of responding will emerge. It could be, for example, that whenever a client talks about their pet, they feel sad, or whenever a client begins to describe a certain event, they change the topic.

Projective techniques were formally introduced in the first half of the 1900s as a means of detecting primary process types of thinking and feeling, including instinctual and motivational processes. Since there were few techniques for understanding the connections in one’s mind at this time, professionals saw projective techniques as having potential for understanding how thoughts and feelings formed a cognitive network. It was assumed that projective techniques would give a window into the thought processes of those with mental disorders and how they differ from the thought processes of healthy individuals.

Two of the most well-known projective techniques are the Rorschach inkblots and the Thematic Apperception Test (TAT). Both of these tests have a long history of use, although various researchers have been critical of the Rorschach and other projective techniques and suggest clinical situations in which these types of techniques are not useful (Garb et al., 2005).

Rorschach Inkblots

During the early part of the 1900s, Herman Rorschach, a Swiss psychiatrist, experimented with using inkblots. The Rorschach inkblots were made by simply dripping ink on a piece of paper and then folding it in half to create a symmetrical design. Some of the inkblots were in black and white (Figure 4.1), and others were in color (Figure 4.2). He initially gave his inkblots to a large number of schoolchildren (Ellenberger, 1970). Rorschach was interested in the sensory processing of these images, which he connected with Carl Jung’s idea of introversion and extraversion.

Rorschach saw introversion as focusing on the inner world of kinesthetic images and creative activity. Extraversion, on the other hand, was a focus on color, emotion, and adjustment to reality. For Rorschach, the content of what was seen in the inkblot was less the focus of the interpretation than the elements used, such as whether the person saw whole images or focused on small details of the blot. Viewing the image as containing movement and the use of the colors was also seen as important. A limited number of 10 plates were selected, and Rorschach published a book on the subject in German, Psychodiagnostics, in 1921. He died some months later at age 37. His book was translated into English in 1942.

Following Rorschach’s death, various clinicians used the inkblot test in their clinical practice. For a number of years, there was little scientific data concerning the reliability and validity of the measure. Since the late 20th century, there has been a movement to standardize the presentation of the test and the manner in which it is scored. Exner (1986, 2003) offered one such system. Various studies have examined the reliability and validity of the measure with specific diagnostic groups and theoretical constructs (Hunsley & Mash, 2007; Meyer, 2001; Meyer & Archer, 2001; Mihura et al., 2019). In 2001, a special issue of the journal Psychological Assessment was devoted to clarifying the utility of the Rorschach along with its problems from an evidence-based position. To address questions of reliability and validity, a series of norms using the Exner system based on more than 5,800 people from 17 countries was published (Meyer et al., 2007). The Meyer et al. review showed consistency across samples for adult Rorschach responses but problems with data from children. Overall, the Rorschach and its scoring is a complicated process that continues to be a focus of scientific debate. One focus is an attempt to link the Rorschach to neuroscience principles (Erdberg, 2019; Jimura et al., 2021; van Graan, 2021).

To respond to the problems of the Exner scoring system, professionals interested in the Rorschach created a simpler scoring system referred to as the Rorschach Performance Assessment System (R-PAS) (see For Further Reading). The basic idea was to create a scoring system with strong psychometric properties such as reliability and validity. The developers of the R-PAS state their goals as follows:

Selecting and highlighting those variables with the strongest empirical, clinical, and response process/behavioral representational support while eliminating those with insufficient support

Comparing test takers’ scores to a large international reference sample, using a graphic array of percentiles and standard score equivalents

Providing a simplified, uniform, and logical system of terminology, symbols, calculations, and data presentation in order to reduce redundancy and increase parsimony

Describing the empirical basis and psychological rationale for each score that is to be interpreted

Providing a statistical procedure to adjust for the overall complexity of the record and a graphical illustration of its impact on each variable

Optimizing the number of responses given to the task in order to ensure an interpretable and meaningful protocol, while drastically reducing both the number of times the task needs to be readministered because of too few responses and the likelihood of inordinately long and taxing administrations because of too many responses

Developing new and revised indices by applying contemporary statistical and computational approaches

Offering access to a scoring program on a secure, encrypted web platform from any device that can interface with the Internet (e.g., PC, laptop, smartphone, tablet)

The R-PAS system was developed around 2006 and continues to be tested worldwide. An initial review and meta-analysis article was published in Psychological Bulletin, which described Rorschach variables with research support and those with little or no support (Mihura et al., 2013). Current research related to R-PAS can be found online (see For Further Reading).

Other researchers have begun to use neuroscience techniques such as brain imaging and electrophysiology to understand physiological processes underlying Rorschach responses. For example, Giromini and his colleagues (2010) examined movement responses on the Rorschach and how these were reflected in the EEG.

Thematic Apperception Test (TAT)

The Thematic Apperception Test (TAT) is composed of 30 black-and-white drawings of various scenes and people (Figure 4.3). The instrument was developed by Christiana Morgan and Henry Murray in the 1930s. Typically, an individual is shown 20 of the cards, one at a time, and asked to create a story about what is being depicted on the card. The basic idea is that by noting the content and emotionality of the individual’s responses, it is possible to gain insight into their thoughts, emotions, and motivations, including areas of conflict. For example, if an individual described many of the cards in terms of someone leaving another person, the clinician might ask if abandonment was an important issue for the person. Although the TAT technique may be useful to gain additional information concerning a person (e.g., suicidal thoughts), it lacks scientific evidence to make it useful in obtaining a formal diagnosis. Similar problems of reliability and validity exist with the TAT as with the Rorschach.

Overall, projective techniques have been the subject of great debate and controversy. Frick and colleagues (2010) presented some of the major pros and cons concerning the use of projective techniques (Table 4.1). Some professionals see their value not in terms of giving exact diagnoses but in their ability to allow a professional to see how an individual responds to ambiguous stimuli, especially in terms of suicidal ideation as well as disorganized thought processes. This may lead to further discussions of areas that a professional would not normally discuss. The major disadvantage of projective techniques centers on questions of validity in terms of both the test’s ability to identify specific disorders and the reliance of the test interpretation on a specific population, such as children.

Table 4.1 Pros and Cons of Projective Tests

Pro Con

Less structured format allows clinician greater flexibility in administration and interpretation and places fewer demand characteristics that would prompt socially desirable responses from an informant. The reliability of many techniques is questionable. As a result, the interpretations are more related to characteristics of the clinician than to characteristics of the person being tested.

Allows for the assessment of drives, motivations, desires, and conflicts that can affect a person’s perceptual experiences but are often unconscious. Even some techniques that have good reliability have questionable validity, especially in making diagnoses and predicting overt behavior.

Provides a deeper understanding of a person than would be obtained by simply describing behavioral patterns. Although we can at times predict things we cannot understand, it is rarely the case that understanding does not enhance prediction (Gittelman-Klein, 1986).

Adds to an overall assessment picture. Adding an unreliable piece of information to an assessment battery simply decreases the overall reliability of the battery.

Helps to generate hypotheses regarding a person’s functioning. Leads one to pursue erroneous avenues in testing or to place undue confidence in a particular finding.

Nonthreatening and good for rapport building. Detracts from the time an assessor could better spend collecting more detailed, objective information.

Many projective techniques have a long and rich clinical tradition. Assessment techniques are based on an evolving knowledge base and must continually evolve to reflect this knowledge.

Credit: Frick, P. J., Barry, C. T., & Kamphaus, R. W. (2010). Clinical assessment of child and adolescent personality and behavior (p. 226). Springer. https://doi.org/10.1007/978–1-4419–0641–0_10; reproduced with kind permission from Springer Science+Business Media.

Neuropsychological Testing

Neuropsychological tests have been developed to help mental health professionals assess a person’s general level of cognitive functioning. Intelligence tests, for example, are able to compare a given individual with their peers to determine their level of functioning. The common intelligence tests, such as the Wechsler Adult Intelligence Scale (WAIS), have a number of subscales designed to measure verbal and performance tasks. The verbal tasks include measurements of acquired knowledge, verbal reasoning, and comprehension of verbal information. The performance tasks include nonverbal reasoning, spatial processing skills, attention to detail, and visuomotor integration.

Other neuropsychological tests have been designed to assess specific types of brain functioning as well as brain damage. These include memory, attention, reasoning, emotional processing, and motor processes, including inhibition of action. One advantage of traditional neuropsychological tests is that they have been given to a large number of people so that norms could be established. Thus, it is possible to know whether a 70-year-old individual is showing a normal memory decline in certain areas or if there might be the beginning of a neurocognitive disorder, such as Alzheimer’s disease.

Although neuropsychological testing was initially developed to assess brain damage resulting from accidents, strokes, or war, it is now finding a use in delineating deficits in those with mental illness. Today, there is a coming together of neuropsychological tests, measures of cognitive processes in normal individuals, and brain imaging techniques. For example, the Wisconsin Card Sorting Test (WCST) requires that an individual sort cards into four piles. Each card has a specific shape on it, such as a circle or square, and a specific number of these shapes. Each card is also printed in a specific color. Thus, you could sort the cards by shape, by number, or by color. The person administering the test makes note of whether the individual is sorting each card correctly or not. After a number of sorts, the administrator changes the correct sort category. Individuals with frontal lobe damage have difficulty responding to changing demands. Individuals with schizophrenia also have difficulty responding to changing task requirements.

Another test that is commonly used in psychopathology research and assessment is the Continuous Performance Test (CPT), which measures attentional characteristics. In one version of the test, participants are shown a series of letters and must respond whenever a particular letter is displayed. The test then requires that the person respond when one particular letter followed by another letter is displayed. Children with ADHD have problems with this task. Thus, neuropsychological tests are also being used to understand brain processes in those with mental illness.

Neuropsychological Tests and Mental Illness

Neuropsychological tests can help identify cognitive changes associated with a particular disorder. For example, there is a rare occurrence of four sisters who all developed schizophrenia in their 20s. The Genain sisters were monozygotic quadruplets born in the United States in the early 1930s. These sisters were studied throughout their lives in terms of genetic makeup as well as cognitive functioning. When the sisters were 66 years of age, Allan Mirsky and his colleagues (2000) readministered a number of neuropsychological tests including the WAIS, the CPT, and the WCST. The scores for each sister at age 66 were compared with their performance at ages 27 and 51. By showing that the test scores of the sisters over their lifetime had not changed, these researchers were able to show that cognitive decline is not part of schizophrenia.

Using Neuroscience Techniques to Identify Mental Illness

As more and more researchers and clinicians have come to see mental illness as representing problems with the brain, there have been a variety of projects to utilize neuroscience approaches to describe psychopathology (Andreasen, 2001). These have ranged from identifying the presence of certain genes and the manner in which they turn on and off in psychopathology to structural and functional descriptions of brain processes and psychophysiological changes measured throughout the body. The potential for using neuroscience approaches to classify mental illness and inform its treatment is an important one (see Clark et al., 2017; Cuthbert & Insel, 2010, 2013; Glannon, 2015; Halligan & David, 2001; Hyman, 2007, 2010; Insel, 2009; Miller, 2010; Sumner et al., 2015).

Traditionally, psychopathology has been defined in terms of signs and symptoms. The experiences of the client and what is observed by the professional are one level of analysis. In general, the mental health professional identifies symptoms that group together and the time of their appearance. Neuroscience techniques offer another level of analysis. From a research standpoint, scientists have sought to identify underlying markers associated with specific mental disorders. Using various brain imaging techniques described in Chapter 2, such as magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI), electroencephalography (EEG), and magnetoencephalography (MEG), there has been a search for structural and functional changes associated with psychopathology. For example, researchers have been able to distinguish individuals with autism (Ecker et al., 2010) and with bipolar disorder (Rocha-Rego et al., 2013) from those without the disorder based on fMRI data.

Part of the potential for using neuroscience markers is related to the fact that not every individual with schizophrenia, for example, reports the same symptoms. Some individuals describe auditory hallucinations, whereas others describe visual hallucinations. What now is considered as a single disorder may be better represented as separate disorders based on underlying mechanisms. Further, certain mental disorders also show gender differences. For example, females tend to develop schizophrenia later than males, but both males and females show similar rates of the disorder. However, females do show higher rates of mood and anxiety disorders.

Overall, neuroscience methods may lead to better diagnostic procedures as well as understanding the mechanisms of the disorder. For example, genetic research suggests similarities between schizophrenia and bipolar disorder in terms of the genes involved. It is also possible to use neuroscience techniques to follow the course of a disorder over time. One study (Raj et al., 2012) based on brain imaging methods suggests that neurocognitive disorders follow specific pathways in the brain. Another potential for neuroscience methods is that by knowing the underlying brain and genetic processes involved in a particular disorder for a particular person, it would be possible to create a treatment that is designed specifically for that individual.

Over the past 100 years, there have been a variety of debates on how to diagnose and classify mental disorders. In the past 50 years, the emphasis has been on reliability of diagnosis such that mental health professionals in one location would diagnose the same individual in the same manner as professionals in another location. As part of this emphasis, there has been a push for observable characteristics that would define a specific disorder. Such characteristics as depressed mood over the day, diminished interest in activities, weight loss, insomnia, fatigue, feelings of worthlessness, difficulty thinking, and thoughts of suicide would be considered in the diagnosis of depression. These types of criteria make up the structure of the Diagnostic and Statistical Manual of Mental Disorders (DSM), published by the American Psychiatric Association (APA), and the International Classification of Diseases (ICD), published by the World Health Organization (WHO). The DSM is used in North America, whereas the ICD is used in Europe. In general, the criteria used in the DSM and ICD are signs and symptoms that are delineated through observation of, and conversation with, the individual.

Categorical Versus Dimensional Approaches

The historical considerations of psychopathology emphasized careful observation and interaction with the afflicted individuals as important methods for understanding the nature of the disorder. Based on these observations of symptoms and signs, individuals were diagnosed and classified as falling into discrete categories of disorders. This is an important level of analysis and one emphasized throughout this book. However, there are other levels of analysis for understanding psychopathology.

With progress in the neurosciences in general and in brain imaging and genetics in particular, other levels of analysis have become possible. These new levels of analysis offer different perspectives for the field of mental illness. What seemed like discrete categories of psychopathology previously are now seen to cluster in new and different ways when considered from the standpoint of genetics. Additional groupings have emerged as scientists have considered the neural networks involved in particular manifestations of psychopathology. This has led to the realization that mental disorders can be described in both a categorical and a dimensional manner.

As shown in the physical sciences, there are times in which a phenomenon can be described both categorically and dimensionally. For example, when water is heated, the rise in temperature can be described in a dimensional manner in terms of a certain number of degrees. However, at a critical point, the water turns to steam, which is a categorically different state from water. Likewise, a reduction in temperature changes water into a different categorical state—ice. The question for the study of psychopathological disorders is to determine the underlying dimensional changes that are associated with categorical-like transformations leading to a disordered state. Further, different underlying processes may actually allow for the presence of more than one disordered state at the same time.

Comorbidity and Hierarchical Approaches to Psychopathology

Technically, when an individual is seen to have more than one disorder at the same time, the disorders are referred to as comorbid. In the National Comorbidity Survey, a large number of individuals with one disorder were found to have one or more additional diagnoses (Kessler et al., 1994). For example, individuals with generalized anxiety disorder will often also show symptoms of depression. Further, these two disorders have overlapping genetic and environmental risk factors (Kendler et al., 1992). The number of diagnoses found in the National Comorbidity Survey was associated with the severity of the symptoms. This has suggested to researchers that there exists a general underlying vulnerability to psychopathology that may be independent of the particular symptoms expressed (Forbes et al., 2021; Lahey et al., 2017; Marshall, 2020; Pittenger & Etkin, 2008; Smith et al., 2020; Widiger, 2021). This general factor of psychopathology, also called the p factor, reflects a number of overlapping considerations, including brain and genetic ones (Hong et al., 2023; Sprooten et al., 2022; Zald & Lahey, 2017).

Historically, researchers sought to determine which disorders tend to co-occur with one another. Initially, two clusters were found. The first is referred to as internalizing disorders. The focus of these disorders, which include anxiety and depression, is the inner world of the person. The second cluster is referred to as externalizing disorders; the behavioral focus of these disorders is the external environment of the person. Externalizing disorders include conduct disorder, oppositional defiant disorder, antisocial personality disorder, substance use disorder, and, in some studies, attention deficit/hyperactivity disorder (ADHD). Studies of comorbidity clusters have led scientists to search for common factors, such as genetics, brain processes, and environmental risk profiles, that might be associated with each cluster. Overall, research has supported the idea that mental disorders can be clustered and that it is possible to identify underlying risk factors (Kendler et al., 2011; Scott et al., 2020).

It is not surprising that with new scientific discoveries the field of psychopathology is experiencing changing perspectives. One of these is the Hierarchical Taxonomy of Psychopathology (HiTOP). Later in the chapter we will also examine the RDoC approach developed by the U.S. National Institute of Mental Health.

The HiTOP consortium was formed in 2015 as a grassroots effort to articulate a fully research-based classification of psychopathology (see For Further Reading). The consortium’s resulting HiTOP model (Figure 4.4) is a system for classifying signs and symptoms of psychopathology (Conway et al., 2022; DeYoung et al., 2022; Kotov et al., 2021; Michelini et al., 2021). Three fundamental findings have shaped HiTOP. First, psychopathology is best characterized by dimensions rather than categories. Second, signs and symbols are best examined in terms of how they occur together. And third, psychopathology can be organized hierarchically from narrow to broad dimensions. This is consistent with research suggesting a general underlying vulnerability to psychopathology that may be independent of any particular symptoms expressed. There are also efforts to link the RDoC and HiTOP approaches (Michelini et al., 2021).

As noted, there has been a push to find more objective markers that can be used in the diagnosis and treatment of mental disorders using neuroscience research. With the advent of the various levels of analysis available to neuroscientists, including brain imaging, genetics, biochemical and electrophysiological processes, brain networks, behavior, and experience, a variety of researchers have sought to describe cognitive, emotional, and motor processes in both health and illness. This has resulted in a better articulation of what underlies these processes.

One such process is memory. It is possible to describe its underlying mechanism through study of specific brain areas such as the hippocampus, the brain networks involving memory, and the biochemical and structural changes among neurons as new information is retained. With this knowledge, it is also possible to explore psychopathological conditions such as amnesia or delusions that involve the memory system.

Another example is the reward system. Humans seek rewards from a variety of sources, including food, sex, power, acclaim, and affiliation, as well as drugs. A number of studies show that particular brain structures, especially the nucleus accumbens part of the ventral striatum, are influenced by an increase in dopamine during a reward (Figure 4.5). In fact, all addictive drugs result in dopamine release in the nucleus accumbens (Pittenger & Etkin, 2008). Individuals with alcoholism show greater activation to alcohol-related cues in the nucleus accumbens and the anterior thalamus. The activation of the nucleus accumbens also correlates with the degree of craving. One approach involving the reward system is to note its involvement in active reward processes, such as those seen in addiction or mania, as well as those disorders in which reward is reduced, such as depression or schizophrenia (Russo & Nestler, 2013).

Since the beginning of the 21st century, a number of researchers and clinicians have asked whether it would be possible to use neuroscience approaches to classify mental illness and inform its treatment (Cuthbert, 2022; Cuthbert & Insel, 2010; Halligan & David, 2001; Hyman, 2007, 2010; Insel, 2009; Miller, 2010; Sanislow et al., 2010). Part of this desire stems from the fact that not all individuals with depression, for example, report the same symptoms. This suggests to some researchers that there might be different underlying brain processes involved in what appears as a single disorder. By knowing the underlying processes involved in a particular disorder, it would be possible to create a treatment that was specific to a given individual.

Neuroscience perspectives can also help validate theoretical constructs used in a variety of theoretical orientations. For example, Carhart-Harris and Friston (2010) examined the relationship between brain network processes and Freudian constructs. Likewise, DeRubeis and colleagues (2008) examined the different pathways of treatment for depression found in cognitive therapy versus medication. These researchers suggested that cognitive therapy works through a top-down approach by increasing higher cortical functioning associated with the frontal lobes, whereas medication works in a more bottom-up approach by decreasing excessive emotional responsiveness associated with the amygdala.

One large organization emphasizing the utilization of neuroscience information to understand mental illness is the National Institute of Mental Health (NIMH) in the United States (Insel, 2009). Through its research mission, NIMH developed four major objectives:

The plan calls for research that will (1) define the pathophysiology of disorders from genes to behavior, (2) map the trajectory of illness to determine when, where, and how to intervene to preempt disability, (3) develop new interventions based on a personalized approach to the diverse needs and circumstances of people with mental illnesses, and (4) strengthen the public health impact of NIMH-supported research by focusing on dissemination [of] science and disparities in care. (Insel, 2009, p. 128)

These objectives are designed to identify the manner in which brain processes are involved in a specific disorder. The goal is to better describe the course of a mental disorder, including when the first signs appear (even if abnormal processes are not yet seen), so as to use this knowledge to create a treatment related to a given individual and to make these treatments available to all members of society. Thus, traditional neuroscience perspectives that reflect action on the level of genetics, the neuron, and neural networks are integrated with research perspectives related to more system-level cognitive, emotional, and behavioral processes. See LENS: Assessment, Classification, and Clinical Practice: The RDoC Alternative to the DSM for a discussion of the Research Domain Criteria (RDoC) approach that is being explored by NIMH.

Classification is a way to name, organize, and categorize the diversity of symptoms seen in mental disorders. Blashfield and Draguns (1976; see also Blashfield et al., 2010) suggest five different purposes of classification:

As a nomenclature—The purpose here, in giving a name to a disorder, is to present a way for mental health professionals to describe and discuss the clients they see.

As a basis of information retrieval—Classifying disorders allows for individuals who may not be professionals to search for information concerning mental disorders.

As a descriptive system—The name of the disorder summarizes the behaviors, thoughts, and emotions of individuals with the disorder.

As a predictive system—In this case, the classification allows one to know the course of the disorder if untreated and particular treatments that may be effective.

As a basis for a theory of psychopathology—The focus in this case is to use classification to understand the disorder.

Over the past 200 years, numerous systems have been developed concerning the diagnosis and classification of mental disorders. In the past 50 years, the emphasis has been on reliability of diagnosis such that mental health professionals in one location would diagnose the same individual in the same manner as professionals in another location. As part of this emphasis, there has been a push for observable characteristics that would define a specific disorder. These types of criteria make up the structure of the DSM and the ICD. In general, the criteria used in the DSM and ICD are signs and symptoms that are delineated through observation of and conversation with the individual. Since ICD codes are used by many health facilities in the United States, the similarities and differences in ICD and DSM criteria of mental disorders will be noted throughout this book.

International Statistical Classification of Diseases and Related Health Problems

The ICD, currently used in over 100 countries worldwide to classify disorders, has an interesting history. It began with the intent of identifying causes of death.

Based on earlier attempts, a system for recording the cause of death was developed by the French statistician Jacques Bertillon in the late 1800s. This came to be known as the International List of Causes of Death. In 1898, the American Public Health Association suggested that the United States, Canada, and Mexico use this system and support its revision every 10 years. In 1948, the WHO, which collected health-related data worldwide, took over the ICD. The sixth edition of the ICD, published in 1949, included a section related to mental disorders. Currently, the ICD includes two sections, one for medical disorders and the other for mental and behavioral disorders. Because of the ICD’s inclusion of medical disorders, it is used for Health Insurance Portability and Accountability Act (HIPAA) purposes such as insurance in the United States.

ICD-11 is the current version, which was updated in 2018 (see For Further Reading). Mental disorders in the ICD-11 are described as short narratives rather than with specific criteria as seen in the DSM-5-TR.

Diagnostic and Statistical Manual of Mental Disorders

The DSM was created by a group of psychiatrists in the 1940s, who had been involved in directing mental hospitals and mental health services for the U.S. Army and Navy during World War II, and others who were part of the American Psychiatric Association. The first version of the DSM (DSM-I) was published in 1952 (see Grob, 1991).

Origins of the DSM

A number of factors helped to create the initial DSM. One was the search for consistency in diagnosis across clinicians throughout the country. In this sense, the DSM-I sought to bring together and standardize the classifications used in state and private mental hospitals, those classifications developed during World War II, and those used by professionals in private practice. Another factor that gained emphasis during World War II was the realization that environmental stress associated with combat was related to the expression of mental disorders. A related understanding was that these disorders could be treated without prolonged institutionalization. In addition, treatment worked best if begun early in the course of the disorder. This required that professionals be able to differentiate those who could be treated and sent back to battle from those who needed long-term care.

The classification system used by DSM-I divided disorders into two broad categories. The first category encompassed disorders such as Huntington’s chorea or neurocognitive disorders (then called dementias) resulting from brain pathophysiologies. These were disorders that resulted from hereditary origins, infections, long-term drug addictions, tumors of the brain, and other such factors. The second category comprised those disorders that included an environmental component in which the individual found it difficult to cope with their world. This second category was further divided into three different types of disorders. The first was psychosis, including schizophrenia and other psychotic disorders. The second was neurosis, such as anxiety disorders. The third was referred to as character disorders, such as psychopathy, which were involved in forensic decisions. As you will see later, those individuals who demonstrate psychopathic tendencies often find themselves accused of crimes, such as cheating others. In general, it was assumed that the neurotic disorders would be more amenable to psychological treatment.

DSM-II was released in 1968. Although it did not differ greatly from DSM-I, it did offer an opportunity for the mental disorder categories of ICD-8 and DSM-II to be almost identical. This allowed for a worldwide classification system, which increased the ability to collect statistics on particular mental disorders. One difference was that the ICD manual just listed the disorders, whereas the DSM included brief definitions.

During the 1970s, there were a variety of changes in issues of importance to both the scientific and the larger lay community that influenced the next version of the DSM. In the scientific study of psychopathology, there was an increased emphasis on greater precision in describing the signs and symptoms associated with a particular psychopathology. In addition, there was an emphasis on differentiating one disorder from another as well as on using experimental research to inform these definitions. There was also an understanding that some individuals manifest a particular disorder in different ways. For example, as noted earlier in this chapter, some individuals with schizophrenia will hear voices, whereas others will have visual hallucinations.

When DSM-III was released in 1980, it included a number of major changes from DSM-I and DSM-II (see Blashfield et al., 2010). One was that it sought to rely on observable evidence to create a scientific system rather than just focusing on the interpretations of experts in the field. Another change was that DSM-III described disorders in terms of specific criteria rather than the more general descriptions of a disorder seen in DSM-I and DSM-II. DSM-III also introduced a five-level system of axes to give a more complete picture of the person. Axis I described the individual’s psychopathological symptoms. Axis II described the person’s personality or intellectual disability. Axis III described any medical disorders that the person had. Axis IV described significant environmental factors in the person’s life. Lastly, Axis V described the person’s level of functioning and any significant role impairment. Overall, DSM-III sought to be theory neutral and to use only observable terms. DSM-III was adopted in a number of countries and translated into 16 languages. In 1987, DSM-III was revised in terms of diagnostic criteria and referred to as DSM-III-R.

In 1994, DSM-IV was released. One goal of this release was to coordinate this revision with ICD-10. There was also an attempt to increase the scientific evidence underlying the diagnostic criteria for each specific disorder. To achieve this goal, a steering committee composed of 27 members oversaw the work of 13 different work groups. The task of the work groups was a three-step process. The first step was to extensively review the scientific literature related to a particular disorder. The second step was to utilize and reanalyze descriptive data from researchers who studied particular disorders. The third step was to conduct a series of field trials using the diagnostic criteria and to modify the criteria based on these trials. DSM-IV was expanded in 2000 with the publication of DSM-IV-TR (TR stands for text revision). DSM-IV-TR did not make major changes to the diagnostic criteria but did expand the text information describing each disorder.

DSM-5 was released in May 2013 and DSM-5-TR in 2022. The rationale for the changes beginning in DSM-5 can be viewed online (see For Further Reading). The “TR” in DSM-5-TR stands for text revision. DSM-5-TR includes revised text and new references, clarifications to diagnostic criteria, and updates to ICD-10-CM codes since DSM-5 was published in 2013. You may note that DSM went from using Roman numerals in previous editions to Arabic numerals for this edition. According to the DSM-5 development website (see For Further Reading), DSM-5 sought to expand the scientific basis of diagnosis begun in DSM-III by working with the NIMH. An initial conference was held in 1999. Participants developed a series of reports that sought to examine a variety of broad topics beyond diagnosis itself. These topics included developmental issues, gaps in the current system, disability and impairment, neuroscience, nomenclature, and cross-cultural issues. In later papers, age and gender issues were also considered. Further, international organizations such as the WHO, which produced the ICD-11, offered input into the composition of DSM-5 and DSM-5-TR, and a number of conferences were held. There has been an effort to make the DSM and the ICD more similar with each new edition published.

This fifth edition of DSM presents the initial usage of dimensional assessments. As noted earlier, dimensional assessment is designed to determine the severity of a particular symptom on a continuum, or range, rather than just acknowledging its presence or absence. In addition, what were once considered to be separate disorders are now viewed as part of a spectrum. For example, although individuals with autism, childhood disintegrative disorder, pervasive developmental disorder, and Asperger’s syndrome may vary in their symptoms and abilities, there are similarities to the disorders. Thus, it would be more accurate to describe autism as a spectrum ranging from mild to severe. In DSM-5 and DSM-5-TR, the term Asperger’s has thus been replaced with the term autism spectrum disorder. Another example is bipolar disorder. Someone diagnosed with bipolar disorder may have a number of severe mood episodes involving mania and depression, or they may have just a few. Dimensional analysis allows for more accurate representation of the disorder by reflecting the severity of these conditions. However, as you will see throughout this book, DSM-5-TR still describes a number of disorders that use a categorical definition. That is, if the person meets the criteria, the person has the disorder, and if they do not meet the criteria, they would not be considered to have the disorder. The following table shows the diagnostic criteria for diagnosing a specific phobia, for example. As you can see in Table 4.2, DSM-5-TR lists a number of different criteria, including duration and intensity, for the clinical diagnosis to be made.

Table 4.2 DSM-5-TR Diagnostic Criteria for Specific Phobia

A. Marked fear or anxiety about a specific object or situation (e.g., flying, heights, animals, receiving an injection, seeing blood).

Note: In children, the fear or anxiety may be expressed by crying, tantrums, freezing, or clinging.

B. The phobic object or situation almost always provokes immediate fear or anxiety.

C. The phobic object or situation is actively avoided or endured with intense fear or anxiety.

D. The fear or anxiety is out of proportion to the actual danger posed by the specific object or situation and to the sociocultural context.

E. The fear, anxiety, or avoidance is persistent, typically lasting for 6 months or more.

F. The fear, anxiety, or avoidance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.

G. The disturbance is not better explained by the symptoms of another mental disorder, including fear, anxiety, and avoidance of situations associated with panic-like symptoms or other incapacitating symptoms (as in agoraphobia); objects or situations related to obsessions (as in obsessive–compulsive disorder); reminders of traumatic events (as in posttraumatic stress disorder); separation from home or attachment figures (as in separation anxiety disorder); or social situations (as in social anxiety disorder).

Specify if:

Code based on the phobic stimulus:

F40.218 Animal (e.g., spiders, insects, dogs).

F40.228 Natural environment (e.g., heights, storms, water).

F40.23x Blood-injection-injury (e.g., needles, invasive medical procedures).

Coding note: Select specific ICD-10-CM code as follows: F40.230 fear of blood; F40.231 fear of injections and transfusions; F40.232 fear of other medical care; or F40.233 fear of injury.

F40.248 Situational (e.g., airplanes, elevators, enclosed places).

F40.298 Other (e.g., situations that may lead to choking or vomiting; in children, e.g., loud sounds or costumed characters).

Coding note: When more than one phobic stimulus is present, code all ICD-10-CM codes that apply (e.g., for fear of snakes and flying, F40.218 specific phobia, animal, and F40.248 specific phobia, situational).

Credit: Reprinted with permission from the Diagnostic and Statistical Manual of Mental Disorders, fifth edition, text revision, DSM-V-TR, pp. 224–225 (Copyright © 2022). American Psychiatric Association. All Rights Reserved.

The DSM-5-TR suggests that every case must begin with a careful clinical history as well as an understanding of the social, psychological, and biological factors that have contributed to the development of the disorder. It is important to understand the nature of the distress that the person is experiencing, since distress is a critical component of a DSM disorder. It is also important to understand if the distress and the individual’s behavior should be considered as part of a mental disorder or simply as deviant from the individual’s cultural, religious, or other significant groups. Thus, DSM-5-TR is more than just a list of symptoms to be checked off by the mental health professional. It is seen as a manual for organizing types of symptoms, which can suggest treatment approaches. However, DSM-5-TR does not specify any particular treatment.

Although DSM-5-TR suggests that the person be considered within a larger context, it dropped the multiaxial system seen in DSM-III and DSM-IV. A clinician may continue to note cultural, environmental, and other conditions related to a given disorder, but Axes III, IV, and V are now eliminated. Further, personality disorders are no longer described on a separate axis (Axis II).

Another change from previous versions is in DSM-5-TR’s organization. The placement of disorders is based on underlying vulnerabilities as well as symptom characteristics. The chapters are organized by general categories such as neurodevelopmental, emotional, and somatic to reflect how a variety of disorders may have common underlying similarities. Recent advances in brain imaging, genetics, and the neurosciences have suggested similarities not understood previously. For example, genetic research has suggested a closer connection between schizophrenia and bipolar disorder than was previously assumed. However, these still remain as separate disorders in DSM-5-TR. A detailed list of changes from DSM-IV to DSM-5 and DSM-5-TR can be found online (see For Further Reading).

Since DSM-5-TR is used in a variety of settings, it carries with it a number of difficulties (Frances & Widiger, 2012). DSM-5-TR is used by mental health professionals to assess individuals. It has also traditionally been used by researchers to study psychopathology. Further, our legal system uses it in court trials in which the outcomes can depend on whether the person is experiencing a mental disorder. All of these usages carry with them different types of demands. The researcher seeks to understand underlying processes of a disorder, whereas the clinician seeks to know how to use the diagnosis to define treatment and induce change. As you will see in later chapters, cultural considerations also play a role. For example, in earlier editions of the DSM, “homosexuality” was considered a disorder that could be treated. In later chapters of this text, feature boxes that highlight changes to and criticisms of DSM-5 and DSM-5-TR in relation to specific disorders will be presented.

Psychological assessment is the process of gathering information about a person in order to make a clinical decision about that person’s symptoms. Most mental health professionals use a clinical interview to initially gather information concerning the status of an individual with whom they are working. Worldwide, the clinical interview, referred to as the mental status exam, has been organized into major assessment categories, including the person’s appearance and behavior, mood and affect, speech quality, thought processes, perceptions and general awareness of surroundings, and intellectual functioning and insight. With the most recent edition of the DSM (DSM-5-TR), the SCID has been developed to set forth specific assessment questions in a structured approach along with a decision tree for directing follow-up questions. Over the past 40 years, there has been an increasing awareness that mental illness takes place within the context of a particular culture, and a fuller understanding of psychopathology requires an understanding of this context. With DSM-5-TR, the Cultural Formulation Interview (CFI) has been developed to help mental health professionals obtain information concerning the person’s culture.

Concerns about the accuracy of assessment and classification of psychopathology require us to consider questions of reliability and validity: (a) whether the person being assessed is giving us accurate information and (b) whether the assessment instrument measures the construct consistently (reliability) and accurately (validity). In terms of assessment, there are a number of types of reliability: internal reliability, test–retest reliability, alternate-form reliability, and inter-rater reliability. Although measures such as neuropsychological tests, brain images, and molecular and genetic changes suggest possible variables to be considered, there is currently no exact measure by which to diagnose psychopathology. This makes validity an important but complex concept. In terms of assessment, there are a number of types of validity: content validity, predictive validity, concurrent validity, and construct validity.

There are several models of assessment that represent different ways of assessing signs and symbols. These include symptom questionnaires, personality tests, projective tests, and neuropsychological testing. Neuroscience techniques offer an additional level of analysis to the models of assessment that focus on signs and symbols. Scientists have sought to identify underlying markers associated with specific mental disorders. Using various brain imaging techniques such as MRI, fMRI, EEG, and MEG, there has been a search for structural and functional changes associated with psychopathology. There might be different underlying brain processes involved in what appears as a single disorder. Thus, neuroscience methods may lead to better diagnostic procedures. It is also possible to use these techniques to follow the course of a disorder over time. Another potential for neuroscience methods is that by knowing the underlying brain and genetic processes involved in a particular disorder for a particular person, it would be possible to create a treatment particular to a given individual.

Classification is a way to organize the diversity seen in mental disorders. Over the past 200 years, numerous systems have been developed; however, in the past 50 years, the emphasis has been on reliability of diagnosis. There has been a push for observable characteristics that would define a specific disorder—signs and symptoms delineated through observation of, and conversation with, the individual. In general, these types of criteria make up the structure of the DSM, published by the APA and used in North America, and the ICD, published by the WHO and used in Europe. One overall change in DSM-5 and DSM-5-TR is the use of dimensional assessments and spectrum-related disorders. Another change is in the placement of disorders based on underlying vulnerabilities as well as symptom characteristics to reflect how a variety of disorders may have some common underlying similarities. The National Institute of Mental Health (NIMH) has begun a program to better study, prevent, and treat mental disorders, which includes developing a new way to classify mental disorders, referred to as Research Domain Criteria (RDoC).

Review Questions

What are some of the advantages of conducting a structured interview for an initial mental health assessment? In addition, what specific advantages do the mental status exam and the SCID offer?

How do reliability and validity relate to the assessment and classification of psychopathology?

How can neuropsychological testing help us understand mental illness?

What important areas of potential do neuroscience techniques offer in the assessment and classification of mental illness?

“Classification is a way to organize the diversity seen in mental disorders.” From what you have read about ICD and DSM, the advantages of classification are clear, but are there any disadvantages or things that are overlooked?

Some critics argue that classification systems may oversimplify the complexities of mental disorders, leading to stigmatization or misdiagnosis. Additionally, reliance on categorical diagnoses might obscure the dimensional aspects of mental health, where symptoms exist on a spectrum rather than fitting neatly into predefined categories.