Genetic explanation

• Genetic explanation

  1. Genetic vulnerability
  2. Candidate genes
  3. OCD is polygenic
  4. Different types of OCD
• Genetic Vulnerability

  • diathesis-stress model says certain genes create OCD vulnerability but require an environmental trigger
• Candidate genes

  • specific genes which create the vulnerability
  • COMT gene - dopamine
  • SERT gene - serotonin
• OCD is polygenic

  • not caused by one gene but possibly up to 230 different ones
• Different types of OCD

  • caused by different groups of genes in different people - etiologically heterogeneous
• (G) + Good supporting evidence

  • study reviewed findings from twin studies and found 68% identical and 31% non shared OCD --> showing strong genetic influence

  - Concordance rate isn't 100% for identical twins so there must be other factors
• (G) - Too many candidate genes

  • not much success in pinning down specific genes and each one only increases the risk fractionally so its unlikely it will ever be useful

  + Small amount of utility for predicting risk of developing OCD
• (G) - Environmental risk factor

  • study found over 50% of OCD patients had suffered trauma, more trauma = more OCD, but not 100% so questions diathesis-stress model