The biological Approach to explaining OCD Flashcards
Genetic Explanations- The COMT gene
COMT regulates the production of the neurotransmitter dopamine that has been implicated in OCD. All genes come in different forms and the one that forms the COMT gene has been found to be more common in OCD patients than people without the disorder. Tukel et al found that this variation produces lower activity of the COMT gene and higher levels of dopamine
Genetic explanations- The SERT gene
Effects the transport of the serotonin, creating lower levels of this neurotransmitter .
One study found a mutation of this gene in two unrelated families where 6 of the 7 family members had OCD(Ozaki et al)
Genetic explanations-Diathesis stress model
Certain genes leave some people more likely to suffer mental disorder but it is not certain- some environmental stress is necessary to trigger the condition. Therefore some people could possess the COMT and SERT gene variations but suffer no ill effects
Neural explanations- The role of serotonin
Serotonin helps regulate mood. Low levels of serotonin means that normal transmission of mood relevant information does not take place and sometimes other mental processes are affected.
Pigott et al found that antidepressants that increase serotonin activity have been shown to reduce OCD symptoms.
Jenicke found out that antidepressants that have a less effect on serotonin do not reduce OCD symptoms
Neural explanations-decision making systems
Some OCD cases seem to be associated with impaired decision making. This in turn may be associated with abnormal functioning of the frontal lobes. They are responsible for logical thinking and making decisions. Also parahippocampul gyrus is associated with processing unpleasant emotions,functions abnormally in OCD
Evaluation on Genetic explanation-good supporting evidence
Some people are vulnerable to OCD as a result of genetic make up. Nestadt et al reviewed twin studies which he found that 68% of identical twins shared OCD . Suggests there is a genetic influence
Evaluation on Genetic explanation-Too many candidate genes
Several genes are involved and each genetic variation only increases the risk of OCD by a fraction. Consequence is that genetic explanation is unlikely to ever be very useful because it provides little predictive value
Evaluation on Genetic explanation-Environment risk factors
Diathesis stress model proves that environmental factors can also trigger or increase the risk of developing OCD. Cromer found that OCD patients had some traumatic events in their past and that OCD was more severe with people who have more than one trauma. Suggets that OCD cannot entirely be genetic in origin
Evaluation on Neural explanations-Some supporting evidence
Some drugs are effective in reducing OCD symptoms and this suggest that the serotonin system is involved in OCD. This suggests that the biological processes that cause the symptoms in those conditions may also be responsible for OCD
Evaluation on Neural explanations-it is not clear exactly what neural mechanisms are involved
Research has identified other brain systems that may be involved sometimes but no system has been found that always plays a role in OCD. We cannot therefore really claim to understand the neural mechanisms involved in OCD.
Evaluation on Neural explanations-We should not assume the neural mechanisms cause OCD
Various transmitters and structures of the brain do not function properly in patients with OCD. However this is not the same as saying that this is abnormal functioning causes the OCD. These biological abnormalities could be the result of OCD rather than its cause
Evaluation extra-Serotonin- OCD link may be simply co-morbidity with depression
People with OCD become depressed and this depression involves disruption to the serotonin system. This could mean that serotonin system is disrupted in many patients with OCD because they are depressed as well
