The biological approach to explaining OCD

• Outline the neural explanation for OCD.

  One neural explanation for OCD suggests a fault in the brain's worry circuit, involving the orbitofrontal cortex (OFC), caudate nucleus, and thalamus. A damaged caudate nucleus fails to suppress worry signals from the OFC, leading to a hyperactive thalamus and obsessive thoughts. Another explanation links OCD to neurotransmitter imbalances—low serotonin causes obsessive thinking and anxiety, while high dopamine leads to compulsions by reinforcing reward-seeking behavior.
• Outline the genetic explanation for OCD.

  OCD may be linked to genetic variations affecting neurotransmitter levels. An overactive SERT gene increases serotonin reuptake, leading to low serotonin levels, which contribute to obsessive thoughts and anxiety. Meanwhile, an underactive COMT gene reduces dopamine breakdown, resulting in high dopamine levels, reinforcing compulsive behaviors through reward-seeking mechanisms.
• What is a strength of the neural explanation for OCD?

  Supporting evidence – Brain scans show higher activity in the OFC and reduced brain tissue in the caudate nucleus in people with OCD, supporting the idea of abnormalities in the worry circuit. (Adds credibility)

  Supporting evidence – Twin studies show higher concordance rates for OCD in MZ twins (who share 100% of genes) than in DZ twins (who share 50%), suggesting a genetic influence. (Adds credibility)
• How have neural and genetic explanations led to practical applications?

  Drug treatments – Understanding serotonin's role has led to SSRIs, which increase serotonin levels and effectively reduce OCD symptoms. (Adds credibility)
• Why do neural and genetic explanations overlook environmental factors?

  Drug therapy is only effective for ~50% of OCD patients, suggesting other causes. Over half of people with OCD have experienced trauma, indicating environmental influences. (Questions credibility)
• Why are neural and genetic explanations biologically reductionist?

  They explain OCD only in terms of biology, ignoring other influences. The diathesis-stress model suggests OCD develops due to a genetic/neural vulnerability combined with a stressor, meaning biological factors alone are insufficient. (Questions credibility)