biological approach to explaining OCD

• genetic explanations- researchers have identified specific genes which create a vulnerability for OCD, called candidate genes. Dopamine genes are also implicated in OCD and may regulate mood. Taylor found evidence that up to 230 different genes may be involved in OCD meaning it is polygenic. There are also different types of OCD. For example, one group of genes may cause OCD in one person but a different group of genes may cause the disorder in another person
• neural explanations- low levels of serotonin lowers mood. For example, if a person has low levels of serotonin then normal transmission of mood relevant information doesn’t take place and mood is affected. Some cases of OCD seem to be associated with impaired decision making. This may be associated which abnormal functioning of the lateral frontal lobes whigh are responsible for logical thinking and making decisions. There is also evidence to suggest that an area called the left parahippocampal gurus, associated with processing unpleasant emotions
• One strength of genetic explanations is that there is evidence. Nestadt et al. reviewed twin studies and found that 86% of identical twins shared OCD as opposed to 31% of non identical twins. Marine and Stebnicki found that a person with a family member with OCD is around 4 times as likely to develop it as someone without. This means that people who are genetically similar are more likely to share OCD, supporting a role for genetic vulnerability.
• One limitation of genetic explanations is the existence of environmental risk factors. Genetic variation affects vulnerability to OCD, but there are also environmental risk factors that trigger or increase the risk of OCD. Cromer et al. found in one sample over half of people with OCD experienced a traumatic event. OCD severity correlated positively with number of traumas. This means that genetic vulnerability only provides a partial explanation for OCD.
• One strength of neural explanations is supporting evidence. Antidepressants that work on serotonin reduce OCD symptoms. This suggests that serotonin may be involved in OCD. Also, OCD symptoms form part of conditions that are known to be biological in origin. For example Parkinson’s disease. This means that biological factors like serotonin are likely to be involved in OCD.
• One limitation of neural explanations is there is no unique neural system. Many people with OCD also experience depression. This depression probably involves disruption to the action of serotonin. It could simply be that serotonin activity is disrupted in many people with OCD because they are depressed as well. This means that serotonin may not be relevant to OCD symptoms