Bioloigcal Approach Explaining OCD

• OCD is explained as a genetic, inherited disorder with 230 seperate candidate genes found more frequently in OCD patients
• SERT Gene


  Affects the reuptake levels of serotonin system

  • Other identified genes include Gene 9, COMT gene; suggesting that OCD is polygenic
• OCD is explained as neural, with low serotonin levels due to quick removal from synapse before its able to transmit its signal to the post-synapse
• Worry Circuit


  Set of brain structures, including:

  • Orbitofrontal cortex (rational decision making)
  • Basal Ganglia system (especially the caudate nucleus)
  • Thalamus

  Communication between these systems appears to be overactive in people with OCD resulting in obsessive thinking
• (+) A03: Nestadt


  MZ and DZ twins grow up sharing similar environments

  • Concordance of MZ = 68%
  • Concordance of DZ = 31%

  Suggesting that the additional shared DNA is responsible for increased concordance
• (+/-) A03: Diathesis Stress Model


  Explanation combined genetic vulnerability with an environmental factor for the disorder to be developed

  • Cromer found 54% of 265 people with OCD had suffered atleast 1 traumatic life event
• (-) A03: Correlation

  Not causation, concordance rates aren't 100% so must be other factors within the role of the environment, can't be fully genetic
• COMT Gene

  Involved with increased levels of dopamine