Biological approach treating OCD

• Drug therapy for mental disorders

  Aims to increase or decrease levels of neurotransmitters in the brain or to increase/decrease their activity
• Low levels of serotonin are associated with OCD

  Drugs to treat OCD work in various ways to increase the level of serotonin in the brain
• SSRIs (Selective Serotonin Reuptake Inhibitors)


  Standard medical treatment used to tackle the symptoms of OCD
• How SSRIs work

  1. Serotonin is released by presynaptic neurons and travels across a synapse

  2. Serotonin chemically conveys the signal from the presynaptic neuron to the postsynaptic neuron

  3. Serotonin is then reabsorbed by the presynaptic neuron where it is broken down and reused

  4. SSRIs prevent the reabsorption and breakdown of serotonin

  5. This effectively increases levels of serotonin in the synapse and continues to stimulate the postsynaptic neuron
• Dosage and other advice for SSRIs

  • Typical daily dose of fluoxetine (e.g. brand name Prozac) is 20 mg, may be increased if not benefitting the person
  • Drug is available as capsules or liquid
  • It takes three to four months of daily use for SSRIs to have much impact on symptoms
• Combining SSRIs with other treatments

  • Drugs are often used alongside cognitive behaviour therapy (CBT) to treat OCD
  • Drugs reduce a person's emotional symptoms, allowing them to engage more effectively with the CBT
  • Some people respond best to CBT alone, others benefit more when additionally using drugs like fluoxetine
  • Occasionally other drugs are prescribed alongside SSRIs
• Alternatives to SSRIs

  • If an SSRI is not effective after three to four months, the dose can be increased or it can be combined with other drugs
  • Sometimes different antidepressants are tried, as people respond very differently to different drugs
  • Tricyclics (an older type of antidepressant) like clomipramine are sometimes used as a second line of defence for people who don't respond to SSRIs
  • SNRIs (serotonin-noradrenaline reuptake inhibitors) have more recently been used to treat OCD, also as a second line of defence for people who don't respond to SSRIs