Explanation of OCD

• What are the two biological explanations for OCD?

  Genetic and neural explanations
• What are candidate genes?

  Genes which create vulnerability for a specific disorder
• What are the two candidate genes for OCD?

  1, Allele of the COMT gene = increase in dopamine 2, SERT gene - decrease in serotonin
• How does an allele of the COMT gene lead to an increase in dopamine?

  x Produces less COMT, which regulates dopamine x Leads to increase in dopamine as it is not being regulated
• What does excessive dopamine lead to in OCD?

  Compulsions
• What does a decrease in serotonin lead to in OCD?

  Obsessive thoughts and anxiety
• What is an example of a neural explanation for OCD?

  The 'worry' circuit
• What is the 'worry circuit'?

  x OFC sends 'worry signals' to thalamus x Normally suppressed by caudate nucleus x OCD sufferers have damaged caudate nucleus = thalamus being alerted and confirming 'worry' to OFC