Biological approach explaining OCD

• Genetic explanations

  Some mental disorders appear to have a stronger biological component than others, and OCD is a good example of a condition that may be largely understood as biological in nature
• Genetic explanation for OCD


  • Genes are involved in individual vulnerability to OCD
  • OCD runs in families, although what is probably passed on from one generation to the next is genetic vulnerability not the certainty of OCD
• Diathesis-stress model

  Certain genes leave some people more likely to develop a mental disorder but it is not certain, some environmental stress (experience) is necessary to trigger the condition
• Candidate genes

  Genes that create vulnerability for OCD, some are involved in regulating the development of the serotonin system
• OCD is polygenic
• OCD is not caused by one single gene but by a combination of genetic variations that together significantly increase vulnerability</b>
• Up to 230 different genes may be involved in OCD
• Genes associated with the action of dopamine as well as serotonin have been studied in relation to OCD
• Aetiologically heterogeneous

  The origins (aetiology) of OCD vary from one person to another
• Different types of OCD may be the result of particular genetic variations, such as hoarding disorder and religious obsession
• Neural explanations

  The genes associated with OCD are likely to affect the levels of key neurotransmitters as well as structures of the brain
• Role of serotonin

  Low levels of serotonin may lead to abnormal transmission of mood-relevant information and contribute to OCD
• Decision-making systems

  • Some cases of OCD, and in particular hoarding disorder, seem to be associated with impaired decision-making and abnormal functioning of the lateral frontal lobes and left parahippocampal gyrus