psychopathology - biological explanation for OCD Flashcards
What did lewis (1936) suggest
Lewis (1936) observed that 37% of his patients with OCD had parents with OCD and 21% of his patients with OCD had siblings with OCD suggesting it runs in families. Certain genes make it more likely a person will develop OCD.
what did the diathesis stress model suggest
suggests that certain genes leave some people more likely to suffer a mental disorder but environmental stress (experience) is necessary to trigger the condition.
what is the role of candidate genes in OCD
5HT1-D beta is implicated in the efficiency of transport of serotonin across synapses.
What does OCD being polygenic mean
meaning several genes are involved. Taylor (2013) found up to 230 different genes may be involved in OCD
(typically involved in action of dopamine as well as serotonin which are both neurotransmitters that regulate mood).
neural explanations:
explain reduction of the functioning of serotonin system in the brain
Serotonin is a neurotransmitter responsible for regulating mood. Low serotonin means that normal transmission
of mood-relevant information between neurons does not take place and mood and other processes are affected.
neural explanations: explain impaired decision making
explain some cases of OCD (hoarding disorder)
o abnormal brain
functioning of the lateral (side bits) of the frontal lobes of the brain
neural explanations:
what does abnormal functioning of left parahippocampal gyrus mean
involved associated with processing unpleasant emotions
strength of genetic explanation (family studies)
The role of genetic factors is supported by family studies of OCD.
E.g.) For example, Nestadt et al. (2010) reviewed twin studies and found that 68% of identical twins (MZ) shared OCD as opposed
to 31% of non-identical twins (DZ).
Exp) This strongly supports a genetic influence on OCD.
limitation of genetic explantion (too many)
There are too many candidate genes that have been identified with OCD.
E.g.) Psychologists have identified over 230 candidate genes. Many genes are clearly involved and each genetic variation increases
the risk of OCD by only a fraction.
Exp) A consequence of this is that a genetic explanation is unlikely to be very useful because it provides little predictive value.
strength of neural explanations (evidence to support)
P) There is evidence to support the role of certain neural mechanisms in OCD.
E.g.) Antidepressants work purely on the serotonin system, increasing levels of this neurotransmitter and are also effective in reducing
OCD symptoms.
Exp) This suggest that the serotonin system is involved in OCD.
limitation of neural explanations (cause + effect)
) We can not assume that the neural mechanisms cause OCD.
E.g.) There is evidence to suggest that various neurotransmitters and structures of the brain to not function normally in patients
with OCD. However, this is not the same as saying that this abnormal functioning causes the OCD.
Exp) Biological abnormalities could be a result of OCD rather than the cause.
