Biological Explanation of OCD

• This approach says there are two causes for OCD:

  1. Genetic Explanations
  2. Neural Explanations
• The genetic explanation for OCD says that there is evidence to support OCD running in families. This means that some people may inherit a predisposition to be more at risk with OCD. Scientists have discovered that a number of diffeent genes are linked to OCD, meaning it is polygenic. One gene that is identified with a link to OCD is the 5HT1D beta gene, which plays a key role in the serotonin system.
• A strength of the genetic explanation is that there is research evidence that OCD runs in families, and the more genetically similar you are to someone with OCD, the higher yout risk. Twin studies has shown concordance rates of 31% for DZ and 68% for MZ twins. This strongly supports the idea that we inherit a vulnerability to OCD.
• Despite having evidence from twin stusies supporting genetic explanations for OCD, the concordance rates also provide evidence that OCD is not entriely genetic and that the environment has a role to play in how/whether these genes express themselves. If OCD were entirely genetic we would find that MZ twins would have a 100% concordance rate.
• Neural explanations focus on the role of brain chemistry (the balance of certain neurotransmitters) as a possible cause of abnormality, as well as looking at how the shape/structure of the brain may explain psychological disorders.
• Serotonin is known to play a role in regulating mood. Low levels of serotonin can be linked to mood disorders such as depression. Low mood may also be accompanied by cognitive disturbances such as faulty information processing. Low serotonin could be caused by serotonin reuptake transporters acting too quickly in the synapse.
• Some psychologists believe that structural defects in the frontal lobe (orbitiofrontal cortex) which contains that 'worry circuit' could cause OCD. An over active worry circuit is likely to affect decision making and an ability to filter out small worries.