Biological explanation

• OCD Neural explanation:

  • broken loop explanation
  • sensory input is processed by orbital frontal cortex
  • this thought is evaluated by the basal ganglia which decides if action must be taken
  • if something must be done, the basal ganglia will contribute to voluntary motor planning, action and habit formation
  • in OCD, the basal ganglia is not filtering properly, so thoughts that should not be acted upon cause a response, causing compulsions
  • neurotransmitters explanation
  • OCD is caused by a lack of serotonin within the basal ganglia
  • can be treated through SSRIs
• OCD genetic explanation:

  • SERT and COMT gene cause OCD
  • COMT causes abnormal dopamine production
  • SERT causes abnormal serotonin production
• OCD biological explanation evaluation

  + brain scan research show increased activity in the cortico-basal ganglia circuit in suffers of OCD (The loop)

  + antidepressants, particularly SSRIs, which act on serotonin are often effective on people with OCD

  + some OCD sufferers have low serotonin levels

  - SSRIs only work on 50% of OCD sufferers

  - contradictory research

  - deterministic

  - direction of causality is unclear for neurochemical explanations as imbalance of serotonin might be an effect of OCD rather than the cause