P - OCD and the biological approach

Question 1

Genetic explanation of OCD and its evaluation

Answer 1

• Lewis observed that of his OCD patients 37% had parents with OCD and 21% had siblings with OCD. This suggests that there is a genetic vulnerability to OCD, meaning some people appear to be predisposed to develop OCD as a result of their genetic make-up
• Candidate genes; genes that create vulnerability for OCD; Some of these genes are involved in regulation and development of the serotonin system; For example: the gene 5HT1-D beta which is involved in the efficiency of synapse transmission.
• OCD is polygenic meaning it is not caused by one single gene but that several genes are involved. Up to 230 genes different genes may be involved in OCD. This makes it difficult to assess exactly which candidate genes have the greatest influence and therefore, which genes drug treatment should be targeted
• The origin of OCD has different causes. One group of genes may cause OCD in one person but a different group of genes may cause the disorder in another person. This also makes it difficult to know which genes drug treatment should target
• EV: Cromer found that over 50% of all his OCD patients had experience a trauma in their lives, suggesting that environmental factors have an influence on OCD

Question 2

Neural explanation of OCD and its evaluation

Answer 2

• Neural explanation is the abnormal functioning of neurotransmitters and/or brain structures
• One explanation would be an abnormality in the neurotransmitter serotonin. This would result in abnormal transmission of mood relevant information. If a person has low levels of serotonin, mood and sometimes other mental processes are affected
• However, the link of OCD and serotonin may just be co-morbidity with depression. Depression can cause disruption to the serotonin system