genetic explanations for ocd

• One explanation for mental disorders is that they are inherited, meaning that individuals may inherit specific genes from their parents that are related to the onset of OCD
• The SERT gene could also contribute to OCD, however this gene causes lower levels of the neurotransmitter serotonin. These lower levels are also implicated in OCD.
• Diathesis-stress Is the idea that a simple link between one gene and a complex disorder like OCD is unlikely. Single genes can account for things as simple as eye colour but not for complex behaviours. Genes such as SERT are also involved in the development of other disorders
• Diathesis-stress model suggests is that specific individual genes only create vulnerability for OCD as well as other disorders. And it is other factors ‘stressors’ that affect what condition develops or if any disorder develops at all. I.e some people could contain the COMP gene or the SERT gene and still not develop OCD.
• In addition, a meta-analysis of 14 twin studies of OCD found that, on average, MZ twins were more than twice as likely to develop OCD if their co-twin had the disorder than was the case for DZ twins
• (-) This evidence suggests a clear basis for a genetic influence on OCD, however the concordance rate is not 100% which means that environmental factors must play a role too (As suggested in the diathesis-stress model).
• Many studies demonstrate the genetic link to abnormal levels of neurotransmitters. E.g menzies et al used MRI scans to produce images of brain activity in OCD patients and their immediate family members without OCD and also a group of unrelated healthy people. OCD patients and their close relatives had reduced grey matter in key regions of the brain, including the OFC.
• menzies studies supports the view that anatomical differences are inherited and these may lead to OCD in certain individuals. Menzies' conclusions have real world applications as he suggested MRI scans can be used to preemptively detect OCD risk.
• COMT gene regulates the production of the neurotransmitter dopamine, which has been implicated in OCD. One form of the COMT gene has been found to be more common in OCD patients than people without the disorder. This particular variation produces lower activity of the COMT gene and higher levels of dopamine.