Neural explanations of OCD

• People may have abnormal levels of key neurotransmitters or abnormal brain 🧠 circuits leading them to develop OCD
• Abnormal levels of neurotransmitters

  Dopamine levels are thought 🤔 to be abnormally high in those with OCD.

  • This is based on animal studies, high doses of drugs that enhance levels of dopamine induce stereotyped movements resembling the compulsive behaviours found in OCD
• Abnormal levels of neurotransmitters 


  Patients with OCD also have low levels of serotonin

  • This is demonstrated by antidepressant drugs which increase serotonin levels have been shown to reduce OCD symptoms.
  • And, antidepressants that have less effect on serotonin levels do not 🚫 reduce OCD symptoms
• Abnormal brain circuits


  Several areas of the frontal lobe are thought 🧐 to be abnormal in patients with OCD.

  • The caudate nucleus normally surpresses signals from the orbifrontal cortex (OFC) which sends worry signals to the thalamus
  • When the caudate nucleus is damaged, it fails to suppress minor worry signals and the thalamus is alerted, which in turn sends signals back to the OFC, acting as a worry circuit
• Abnormal brain circuits 


  Evidence for abnormal brain circuits is supported by PET scans of OCD patients where the OFC is activated when symptoms of OCD are activated.

  • Serotonin and dopamine are linked to regions of the frontal lobes.
  • Comer reports that serotonin is key 🗝️ to the OFC'S operation & the caudate nuclei, so abnormal levels of serotonin cause these areas to malfunction.
  • Dopamine is the main neurotransmitter in the basal ganglia and high levels of dopamine lead to overactivity of this region