Biochemical factors

• PET scans have shown that levels of serotonin are lower in OCD sufferers
• Evidence for biochemical factors

  Insel found SSRIs can reduce symptoms of OCD in 50% to 60% of cases
• Evidence for biochemical factors

  Zohar et al found SSRIs alleviate symptoms in 60% of patients with OCD
• Evidence against biochemical factors

  SSRIs offer some relief to sufferers but isn't true in all cases
• Evidence against biochemical factors

  Link of OCD and serotonin is correlational meaning other factors could be at play