Neural

• Genes associated with OCD are likely to affect the structure of the brain too
• The role of neurotransmitters

  • Low serotonin = less mood-relevant transmission = obsessions
  • High Dopamine = more motivation-related transmissions = compulsions
• The Worry Circuit

  • Orbitofrontal Cortex normally sends signals to the thalamus about things that are worrying or threatening (obsessions)
  • The Caudate nucleus normally inhibits signals to the OFC once the worrying stimuli is gone
  • If the worry signal is too strong, or the caudate nucleus is too weak, transmissions are constantly sent between OFC and thalamus (resulting in reinforced worry and compulsions)
• Strengths

  • Some supporting evidence - Some antidepressants increase the levels of serotonin, reducing OCD symptoms. Suggests that the biological processes that cause the symptoms in some conditions may also be responsible for OCD
• Weaknesses

  • Serotonin-OCD link may be comorbidity with depression - Depression can be a result of OCD, which disrupts the serotonin system. Could be a result of OCD not the OCD itself
  • We should not assume that neural mechanisms cause OCD - there’s evidence that various functions of the brain function abnormality, however, this could be caused by OCD not because of OCD