The Biological approach to treating OCD

• What is the most common treatment for OCD under the biological approach?

  • SSRIs
  • Antidepressants, e.g. fluoxetine
  • Selective Serotonin Re-uptake Inhibitors
  • Aim to raise serotonin in brain
  • = activity in OFC calmed = worry circuit quietened/broken
  • = obsessions + compulsions prevented
• How do SSRIs work?

  • Serotonin in OFC + caudate nucleus -> inhibitory NT = prevents neurons firing
  • Lack of serotonin = more firing = more anxiety impulses
  • SSRIs prevent reabsorption of serotonin by presynaptic neuron
  • = more serotonin in synaptic gap
  • Postsynaptic neuron stimulated = inhibition of electrical impulse = less likely to fire -> calms worry circuit
• What other drugs to treat OCD exist?

  • Tricyclics
  • Anti-anxiety drugs
• What are tricyclics?

  • Originally antidepressants -> mostly used for OCD now
  • e.g. clomipramine
  • Similar to SSRIs -> prevent reuptake of serotonin AND noradrenaline
  • Used for people resistant to SSRIs
• What are anti-anxiety drugs?

  • e.g. benzodiazepines
  • Slow CNS
  • Enhances activity for GABA
  • GABA = NT -> inhibits neurons, prevents firing
• Biological treatments for OCD A&E point 1: drug therapy is effective at reducing OCD symptoms

  • Soomro et al. (2008) -> meta-analysis of 17 studies
  • SSRIs more effective than placebos up to 3 months post-treatment
  • Julien (2007)
  • Symptoms don't fully disappear -> BUT, symptoms were reduced in 50-58% of patients
  • Allows 'normal' lifestyle
• Biological treatments for OCD A&E point 2: it could be argued that drugs are only effective at reducing symptoms, not targeting the cause

  • Maina et al. (2001)
  • Swift relapse rate when medication stopped -> must not have affected cause greatly if symptoms returned after medication ended
  • Simpson et al. (2004)
  • Up to 45% relapse rate within 12 weeks of finishing medication
  • Psychological therapies in same period only had a relapse rate of 12%!!!
• Biological treatments for OCD A&E point 3: drugs have side effects + withdrawal symptoms

  • SSRIs -> nausea, headaches + insomnia
  • Tricyclics -> more common side effects + worse (hallucinations, irregular heartbeat)