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CHAPTER 2 CONTEMPORARY THEORIES OF ABNORMALITY
- theory: a set of ideas that provide a framework for asking questions about a phenomenon, as
well as gathering and interpreting information about that phenomenon
- Albert Ellis suffered a fear of public speaking
- he believed his fears were due to irrational beliefs
- other theories would suggest alternative causes of his fears
- biological approach would suggest his symptoms were caused by a biological
factor e.g. genetic vulnerability to anxiety
- psychological approach suggests symptoms are rooted in psychological factors
e.g. belief system, early childhood experiences
- social approach would look at his interpersonal relations and social environment
- most theories over history searched for one factor that causes people to develop a disorder
- contemporary theorists recognize that there are often many pathways that lead to the
development of a specific disorder
- vulnerability stress model: a person must carry a vulnerability to the disorder in order to
develop it
- it can be biological (genetic predisposition), psychological (personality trait), social factor
(poor interpersonal relationships)
- to develop the disorder, person must experience some type or stress or trigger
- biological (illness), psychological (violation of trust), social factor (traumatic event)
- feedback effects: change in one factor result in changes in a second factor which feed back to
change the first factor again
Biological Approaches
Structural Brain Abnormalities
- people who suffer damage to the brain (lesions) or who have major abnormalities in the
structure of the brain often show problems in psychological functioning
- location of structural damage influences the psychological problems one can have
- cerebral cortex: area involved in many advanced thinking processes
- hypothalamus: regulates eating, drinking, and sexual behaviour, influences basic emotions
- stimulation in certain areas produce pleasure whereas in other areas produce pain
- limbic system: collection of structures closely interconnected with the hypothalamus and
appear to exert additional control over some instinctive behaviours
- other major structures of the brain (figure 2.5 pg34)
- corpus callosum: bridge of fibres passing information between the two cerebral
hemispheres
- thalamus: relay centre for cortex; handles incoming and outgoing signals
- cerebellum: involved in balance and control of movement
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- medulla: responsible for regulating largely unconscious functions e.g. circulation,
breathing
- pons: involved in sleep and arousal
- reticular formation: network of neurons related to sleep, arousal, and attention
- spinal cord: responsible for communication between brain and rest of body; involved with
simple reflexes
Biochemical Causes of Abnormality
- neurotransmitters: biochemicals that act as messengers, carrying impulses from one neuron
(nerve cell) to another in the brain and in other parts of the nervous system
- each neuron has a cell body and dendrites which receive impulse from adjacent neurons
- impulse then travels down the length of the axon to small swellings at the ends called
synaptic terminals
- there is a slight gap between the synaptic terminals and adjacent neurons called the
synaptic gap, or synapse
- neurotransmitter is released into the synapse and then binds to receptors, molecules on
membranes of adjacent neurons
- binding stimulates adjacent neurons to become more negatively or positively charged
Neurotransmitter Theories
- too much or too little of certain neurotransmitters in the synapses causes specific types of
psychopathology
- amount of neurotransmitter in synapse can be affected by
- reuptake: when the initial neuron releasing the neurotransmitter reabsorbs the
neurotransmitter, decreasing the amount left in the synapse
- degradation: when the receiving neuron releases an enzyme into the synapse breaking
down the neurotransmitter into other biochemicals
- both happen naturally, when one or both malfunction, result in abnormally high/low levels
- psychological symptoms may also be linked to the number and functioning of receptors for
neurotransmitters on the dendrites
- if there are too few receptors or receptors arent sensitive enough, the neuron will be
unable to make adequate use of the neurotransmitter available in the synapse
- if there are too many receptors or they are too sensitive, neuron may be overexposed
- serotonin: regulates emotions and impulses e.g. aggression
- travels through many key areas of the brain
- dopamine: prominent in areas of brain that regulate our experience of reinforcement or
rewards, affected by substances that we find rewarding
- important to functioning of muscle systems
- norephinephrine: produced mainly by neurons in brain stem
- cocaine and amphetamines prolong the action by slowing its reuptake process
- low levels cause a persons mood level to be depressed
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- gamma-aminobutyric acid (GABA): inhibits action of other neurotransmitters
- thought to play an important role in anxiety symptoms
Endocrine System
- system of glands producing chemicals, hormones, which are released directly into the blood
- a hormone carries messages throughout the body, potentially affecting mood, levels of
energy, and reaction to stress
- pituitary gland: “master gland that produces the largest number of different hormones and
controls secretion of other endocrine glands
- hypothalamic-pituitary-adrenal axis (HPA axis) is the relationship between the pituitary gland
and the hypothalamus
Genetic Factors in Abnormality
- behaviour genetics: the study of the genetics of personality and abnormality
- concerned with (1) to what extent are behaviours inherited (2) what are the processes by
which genes affect behaviour?
- most disorders arent the result of single faulty genes but of combinations of altered genes
- polygenic process: it takes multiple genetic abnormalities coming together in one individual to
create a disorder
- scientists use three basic types of studies to determine the heritability of a disorder
Family History Studies
- genetically transmitted disorders should show up more often in families of people with the
disorder than in families of people without it
- scientists first identify people who clearly have the disorder in question, probands
- also identify a control group of people who clearly dont have the disorder
- they then trace the family pedigrees of the individuals in these two groups and determine
how many of their relatives have the disorder
- problem: families also share environment and as a result, environmental stresses
Twin Studies
- if a disorder is determined entirely by genetics, when on monozygotic (MZ) twin has a disorder,
the other should always have it
- concordance rate: the probability that both twins have the disorder if one twin has the disorder
- concordance rate for disorders transmitted partially by genetics should be higher in MZ
twins than for DZ twins
- however studies dont fully separate genetic factors from environmental factors
Adoption Studies
- researchers first identify people who have the disorder of interest who were adopted shortly
after birth
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Document Summary

Theory: a set of ideas that provide a framework for asking questions about a phenomenon, as well as gathering and interpreting information about that phenomenon. Albert ellis suffered a fear of public speaking. He believed his fears were due to irrational beliefs. Other theories would suggest alternative causes of his fears. Biological approach would suggest his symptoms were caused by a biological factor e. g. genetic vulnerability to anxiety. Psychological approach suggests symptoms are rooted in psychological factors e. g. belief system, early childhood experiences. Social approach would look at his interpersonal relations and social environment. Most theories over history searched for one factor that causes people to develop a disorder. Contemporary theorists recognize that there are often many pathways that lead to the development of a specific disorder. Vulnerability stress model: a person must carry a vulnerability to the disorder in order to develop it. It can be biological (genetic predisposition), psychological (personality trait), social factor (poor interpersonal relationships)

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