Schizophrenia

Schizophrenia

Misconceptions:

• Schizophrenia does not mean split personality or multiple personality.

• Most people with schizophrenia are not more dangerous or violent than the general population.

• It is a misconception that people with schizophrenia inevitably end up homeless or living in hospitals. Most live with family, in group homes, or on their own.

Key Facts:

• A chronic brain disorder affecting less than one percent of the U.S. population.

• Affects men and women equally but may have an earlier onset in males.

• Rates are similar around the world.

• People with schizophrenia are more likely to die younger, largely due to high rates of co-occurring medical conditions.

Types of Schizophrenia

• The DSM-5 (2013) no longer uses the previous five subtypes of schizophrenia that were present in the DSM-4.

• The DSM-4 described the following types:

  • Paranoid type: Preoccupation with one or more delusions or frequent auditory hallucinations; other symptoms like disorganized speech/behaviour or inappropriate emotions were not prominent.

  • Disorganized type: Displayed disorganized speech and behaviour, as well as flat or inappropriate emotional expression; did not meet criteria for catatonic schizophrenia. Although no longer a distinct subtype, disorganized speech and thought are still elements of a schizophrenia diagnosis.

  • Catatonic type: Characterized by catatonia, a syndrome causing abnormal physical movements, behaviours, and withdrawal. Symptoms could include mutism, echolalia, echopraxia, and may occur with schizophrenia and other mood disorders. Catatonia is now considered a specifier for schizophrenia and other mood disorders.

  • Undifferentiated type: Involved symptoms that did not fit into the paranoid, disorganized, or catatonic types.

  • Residual type: Absence of prominent delusions, hallucinations, disorganization, or catatonic behaviour, but with continuing disturbance indicated by two or more milder symptoms like odd beliefs or unusual perceptions.

• The reasons for updating the DSM classification included overlapping subtype symptoms and low diagnostic precision. The features of these former types are still considered in a schizophrenia diagnosis but are no longer distinct categories.

Clinical Picture of Schizophrenia

• When active, symptoms can include delusions, hallucinations, disorganized speech, trouble with thinking, and lack of motivation.

• Characterized by episodes where the person is unable to distinguish between real and unreal experiences.

• Severity, duration, and frequency of symptoms can vary, but severe psychotic symptoms often decrease with age.

• Symptoms are often increased by not taking medications, alcohol or illicit drug use, and stressful situations.

• Symptoms fall into three major categories:

  • Positive Symptoms (abnormally present):

    • Hallucinations: Hearing voices or seeing things that do not exist; vivid and clear with an impression like normal perceptions.

    • Delusions: Fixed false beliefs held despite clear or reasonable evidence that they are not true. Paranoia is an example.

    • Exaggerated or distorted perceptions, beliefs, and behaviours.

  • Negative Symptoms (abnormally absent):

    • Impaired emotional expression (affective flattening).

    • Decreased speech output (alogia).

    • Reduced desire to have social contact (asociality).

    • Reduced drive to initiate and persist in self-directed purposeful activities (avolition).

    • Decreased experience of pleasure (anhedonia).

  • Disorganized Symptoms:

    • Confused and disordered thinking and speech: Thoughts and speech that are jumbled or do not make sense, switching topics, or unrelated responses. Severe enough to cause substantial problems with normal communication.

    • Disorganized or abnormal motor behaviour: Ranges from childlike silliness to unpredictable agitation or repeated purposeless movements. Can cause problems in daily activities.

• Cognition is also affected, leading to problems with attention, concentration, and memory, and to declining educational performance.

• Symptoms usually first appear in early adulthood and must persist for at least six months for a diagnosis.

  • Men often experience initial symptoms in their late teens or early 20s.

  • Women tend to show first signs in their 20s and early 30s.

  • More subtle signs may be present earlier, including troubled relationships, poor school performance, and reduced motivation.

• Diagnosis requires a thorough medical examination by a psychiatrist to rule out substance misuse or other neurological or medical illnesses with mimicking symptoms.

• Psychosis refers to a set of symptoms characterised by a loss of touch with reality due to a disruption in brain information processing. Thoughts and perceptions are disturbed, and understanding what is real may be difficult.

Aetiology of Schizophrenia

• The heritability of schizophrenia has been estimated to be as high as 80%.

• Despite high heritability and reduced reproductive success in affected individuals, the genetic variants have not been eliminated, posing an evolutionary paradox. Evolutionary explanations for this paradox have been suggested but do not fully account for triggers like chronic stress or the occurrence of psychosis in other mental disorders. Notably, these hypotheses have not led to better treatments or a cure.

• Despite assumptions of a largely genetic disorder with limited environmental role, studies suggest otherwise. The concordance rate in monozygotic twins is only 28%, and 6% for dizygotic twins, indicating a significant role for non-genetic factors.

• There is no single gene that causes schizophrenia. Thousands of gene variants comprise risk factors, each with a small effect, and many are also associated with other mental disorders.

• Risk profile scores from schizophrenia-associated alleles explain only about 7.7% of the variation in liability, suggesting that genetic factors comprise only a minor part of the aetiology, and the contribution of environmental factors needs further exploration.

• Schizophrenia is characterised by heterogeneity in aetiology, clinical presentation, and prognosis.

• Studies have shown subtle differences in brain structure in some people with schizophrenia, although these are not universal and can occur in individuals without mental illness.

• Neurotransmitters, chemicals carrying messages between brain cells, are thought to be present in different amounts in people with schizophrenia. Medicines lowering certain neurotransmitters like dopamine can help with symptoms, suggesting a key role.

• People who develop schizophrenia are more likely to have experienced complications before and during birth, such as low birth weight, premature labour, and lack of oxygen (asphyxia) during birth.

• Triggers that can cause schizophrenia to develop in at-risk individuals include stress and drug abuse.

• Psychosis can also occur in other conditions like major depressive disorder, bipolar disorder, schizoaffective disorder, and some other diseases such as Alzheimer’s and central nervous infections.