A01

• What is the aim of drug therapy for mental disorders?

  To adjust neurotransmitter levels in the brain
• How do drugs for OCD primarily function?

  They increase serotonin levels in the brain
• What type of antidepressant is commonly used for OCD?

  Selective serotonin reuptake inhibitor (SSRI)
• What is the role of serotonin in the brain?

  It conveys signals between neurons
• How do SSRIs affect serotonin reabsorption?

  They prevent reabsorption and breakdown
• What is a typical daily dose of fluoxetine?

  20 mg
• How long does it take for SSRIs to impact symptoms?

  Three to four months of daily use
• Why are drugs combined with cognitive behaviour therapy (CBT)?

  To reduce emotional symptoms for better engagement
• How do responses to CBT and drugs vary among individuals?

  Some prefer CBT alone, others benefit from drugs
• What happens if an SSRI is ineffective after three to four months?

  The dose can be increased or combined with other drugs
• How does clomipramine compare to SSRIs?

  It has more severe side effects
• What are SNRIs used for?

  To treat OCD when SSRIs are ineffective
• What neurotransmitters do SNRIs increase?

  Serotonin and noradrenaline
• What are the alternatives to SSRIs for treating OCD?

  • Increase SSRI dose or combine with other drugs
  • Try different antidepressants
  • Use tricyclics like clomipramine (more side effects)
  • Use SNRIs for those not responding to SSRIs
• Tricyclics 


  E.g clomipramine

  Acts on several systems including serotonin system but has more side effects
• SNRIs


  serotonin noradrenaline reuptake inhibitor
• SSRIs 


  • Serotonin is released by the presynaptic neurons and travels across a synapse.
  • The neurotransmitter chemically conveys the signal from the presynaptic neuron to the postsynaptic neuron and then it is reabsorbed by the presynaptic neuron where it is broken down and reused.
  • By preventing the reabsorption and breakdown, SSRIs effectively increase levels of serotonin in the synapse and thus continue to stimulate the postsynaptic neuron.