Psychopathology: Explaning OCD Flashcards
what’s the genetic explanation for OCD?
Lewis observed that of his OCD patients 37% had parents with OCD and 21% had siblings with OCD. this suggests OCD runs in families and is passed from one generation to the next is not genetic vulnerability. according the the diathesis-stress model, certain genes leave some people more likely to suffer a mental disorder and an environmental factor may trigger OCD.
what’s candidate genes?
researchers have identified genes which create vulnerability for OCD. some of these genes are involved in the regulation of the development of the serotonin system.
how is OCD polygenic?
this means OCD is caused by several genes, not just one. Taylor has analysed findings of previos studies and found evidence of up to 230 genes involved in OCD. these genes involved are associated with the action of dopamine and serotonin (regulate mood).
what are the different types of OCD?
1 group of genes may cause OCD in 1 person but a different group may cause the disorder in another person (aetiologically heterogeneous), meaning OCD has different causes.
what’s the role of serotonin (neural)?
serotonin helps regulate mood. neurotransmitters are responsible for relaying information from 1 neuron to another. if a person has low serotonin levels then normal transmission of mood-relevant information doesn’t take place and mood is affected.
what’s the decision making system (neural)?
some cases are associated with impaired decision making, which in turn is associated with abnormal functioning of the lateral of the frontal lobes (responsible for logical thinking and decision making). there’s also evidence that the left parahippocampal gyrus is associated with processing unpleasant emotions functions abnormally in OCD.
what’s the supporting evidence of the genetic explanation? (A03)
one of the best sources of evidence for the importance of genes is twin studies. Nestadt reviewed previous twin-studies and found that 68% of MZ twins shared OCD opposed to 31% DZ twins. this strongly suggests a genetic influence on OCD.
what’s the environmental risk factors of the genetic explanation? (A03)
it seems environmental factors can also trigger or increase the risk of developing OCD. Cromer found that over half the OCD patients in their sample had a traumatic event in their past and that OCD was severe in those with more than 1 trauma. this suggets OCD isn’t entirely genetic, that there is also environmental causes.
what’s the supporting evidence of neural explanation? (A03)
some antidepressants work purely on the serotonin system, increasing levels of serotonin. such drugs are effective in reducing OCD symptoms, which suggests serotonin is involved in OCD.
why isn’t it clear exactly what neural mechanisms are involved? (A03)
studies of decision making have shown that these neural system are the same systems that function abnormally in OCD. however, research has also identifed other brain systems that may be involved but no system has been found thta always plays a role in OCD. therefore we can’t claim to understand the neural mechanmisms in OCD.
