Abnormal Psychology: Theories  of Abnormality

Theory: a set of ideas that provides a framework for asking questions about a phenomenon and for gathering and interpreting information about that phenomenon

Therapy: a treatment, usually based on a theory of a phenomenon, that addresses those factors the says cause the phenomenon

Biopsychosocial Approach: recognizing that it is often a combination of biological, psychological, and sociocultural factors that results in the development of psychological symptoms

• Risk Factors: increase the risk of psychological problems
  • Biological: genetic disposition
  • Psychological: difficulty remaining calm in stressful situations
  • Sociocultural: growing up with the stress of discrimination based on ethnicity or race
  • Transdiagnostic Risk Factors: factors that increase risk for multiple types of psychological problems

Diathesis-stress Model

• when the risk factor and the trigger or stress come together in the same individual does the full-blown disorder emerge
• Diathesis: a predisposition toward developing disorder that can derive from biological, psychological, and/or sociocultural causal factors; another term for risk factor

BIOLOGICAL APPROACHES

Brain Dysfunction: one of three causes of abnormality on which biological approaches often focus

3 MAIN REGIONS OF THE BRAIN 

• Hindbrain: includes all the structures located in the hind (posterior) part of the brain, closest to the spinal cord
  • Sits on top of the spinal cord and is crucial for basic life functions
  • Contains
  • Medulla: helps control breathing and reflexes
  • Pons: important for attentiveness and the timing of sleep
  • Reticular Formation: a network of neurons that control arousal and attention to stimuli
  • Cerebellum: concerned primarily with the coordination of movement
• Midbrain: located in the middle of the brain
  • Contains
  • Superior Colliculus and Inferior Colliculus: relay sensory information and control movement
  • Substantia Nigra: a crucial part of the pathway that regulates responses to reward
• Forebrain: includes the structures located in the front (anterior) part of the brain; relatively large and developed compared to that of other organisms
  • Contains
  • Cerebral Cortex/Cortex: outer layer of the cerebrum; involved in many of our most advanced thinking processes
  • Composed of 2 hemispheres on the left and right sides of the brain that connected by the corpus callosum
  • 4 lobes: frontal, parietal, occipital, temporal lobes
  • Subcortical Structures: under the cerebrum
  • Thalamus: directs incoming information from sense receptors (vision and hearing) to the cerebrum
  • Hypothalamus: a small structure just below the thalamus; regulates eating, drinking, and sexual behavior; involved in processing basic emotions
  • Pituitary Gland: the most important of the endocrine system
  • Limbic System: a set of structures that regulate many instinctive behaviors, such as reactions to stressful events and eating and sexual behavior
  • Amygdala: a structure of the limbic system that is critical in emotions such as fear
  • Hippocampus: part of the limbic system that plays a role in memory

Biochemical Imbalances and Genetic Abnormalities: other two causes of abnormality

Biochemical Imbalances

Neurotransmitters

• biochemicals that act as messengers carrying impulses from one neuron or nerve cell to another in the brain and in other parts of the nervous system

Dendrites

• a number of short branches
• Dendrites and and cell body receive impulses from adjacent neurons

Axon

• slender, tubelike extension

Synaptic Terminals

• small swellings at the end of the axon

Synaptic Gap/Synapse

• Slight gap between the synaptic terminals and the adjacent neurons

• The neurotransmitter is released into the synapse then binds to special ^^receptors^^—molecules on the membrane of adjacent neurons

  • This binding works somewhat the way a key fits into a lock
  • The binding stimulates the adjacent neuron to initiate the impulse, which then runs through its dendrites and cell body and down its axon to cause the release of more neurotransmitters between it and other neurons

• The amount of a neurotransmitter available in the synapse can be affected by two processes

  • The Process of Reuptake: occurs when the initial neuron releasing the neurotransmitter into the synapse reabsorbs the neurotransmitter, decreasing the amount left in the synapse
  • Degradation: occurs when the receiving neuron releases an enzyme into the synapse that breaks down the neurotransmitter into other biochemicals
  • Reuptake and degradation happens naturally; when one or both of these processes malfunction, abnormally high or low levels of neurotransmitter in the synapse result

• Psychological symptoms may be the consequence of malfunctioning in neurotransmitter systems; also, psychological experiences may cause changes in neurotransmitter system functioning

Serotonin: a neurotransmitter that travels through many key areas of the brain, affecting the function of those areas; plays an important role in emotional well-being, particularly in depression and anxiety, and in dysfunctional behaviors, such as aggressive impulses

Dopamine: a prominent neurotransmitter in those areas of the brain associated with our experience of reinforcements or rewards, and it is affected by substances, such as alcohol, that we find rewarding; also important to the functioning of muscle systems and plays a role in disorders involving control over muscles

Norepinephrine/Noradrenaline: a neurotransmitter produced mainly by neurons in the brain stem

• Cocaine and amphetamine prolong the action of norepinephrine by slowing its reuptake process

Gamma Aminobutyric Acid/GABA: inhibits the action of other neurotransmitters; thought to play an important role in anxiety symptoms

THE ENDOCRINE SYSTEM

• system of glands produces chemicals called hormones, which are released directly into the blood

Hormone: carries messages throughout the body, potentially affecting a person’s mood, level of energy, and reaction to stress

Pituitary/master gland: produces the largest number of different hormones and controls the secretion of other endocrine glands; lies just below the hypothalamus

Corticotropin-release Factor (CRF)

• carried from the hypothalamus to the pituitary through a channel-like structure
• Stimulates the pituitary to release the body’s major stress hormone, adrenocorticotropic hormone (ACTH)
• Adrenocorticotropic Hormone (ACTH):
  • Carried by the bloodstream to the adrenal glands and to various other organs of the body, causing the release of about 30 hormones, each of which plays a role in the body’s adjustment to emergency situations

Hypothalamic-pituitary-adrenal Axis (HPA axis)

• People who have a dysregulated HPA axis may have abnormal physiological reactions to stress that make it more difficult for them to cope with the stress, resulting in symptoms of anxiety and depression

Behavior Genetics: the study of the genetics of personality and abnormality, is concerned with two questions:

(1) To what extent are behaviors or behavioral tendencies inherited? 

(2) What are the processes by which genes affect behavior?

Interaction Between Genes and Environment:

1. Genetics factors can influence the kinds of environments we choose, which then reinforce our genetically influenced personalities and interests.

2. The environment may act as a catalyst for a genetic tendency.

   1. Epigenetics: indicates that environmental conditions can affect the expression of genes; the study of heritable changes in the expression of genes without change in the gene sequence.

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