Biological: treating OCD: drug therapy

• Synaptic transmission:

  • when a neuron is activated by a stimulus, it generates an electrical impulse (action potential) that travels down the axon of the neuron
  • the gap between one neuron and the next is the synaptic cleft. For the electrical impulse to reach the next neuron, it must travel across the synapse as a chemical signal using neurotransmitters.
• Beginning of synaptic transmission:

  • electrical impulses (action potentials) travel down the axon of the pre-synaptic neuron
  • electrical impulses trigger release of the neurotransmitters from the vesicles e.g. serotonin into the synapse
• Middle of synaptic transmission:

  • neurotransmitters diffuse across the synapse
  • neurotransmitters bind to the receptors on the postsynaptic membrane
• End of synaptic transmission:

  • stimulation of postsynaptic receptors by neurotransmitters result in either excitation or inhibition of the postsynaptic membrane
  • neurotransmitters are reabsorbed into the pre-synaptic neuron
• Drug therapy: SSRIs (Selective Serotonin Re-Uptake Inhibitors)

  • OCD is associated with low serotonin levels
  • SSRIs prevent the re-uptake/reabsorption and break down of serotonin in the pre-synaptic neuron
  • This increases levels of serotonin in the synapse so that it can continue to stimulate the post-synaptic neuron
  • e.g. Fluoxetine (20mg taken daily for 3-4 months to impact symptoms)
• Combining SSRIs with other treatments:

  • Often used alongside CBT as the drugs reduce a patient's emotional symptoms e.g. anxiety. This enables them to engage more fully with CBT.
• Alternative drug treatments to SSRIs:

  • Not all patients respond to SSRIs: not effective? Increase dose or a combination of drugs given e.g. SNRIs (serotonin-noradrenaline re-uptake inhibitors) may work for patients who don't respond to SSRIs. These increase serotonin and noradrenaline levels.
• Drug therapy for OCD: strength

  • Drug therapy is effective at treating OCD
  • Soomro et al: reviewed 17 studies, concluded that in every study, SSRI was more effective than the placebo and that there was a decline in symptoms for 70% of patients (the other 30% were helped with alternative drugs/drugs + psychological therapy e.g. CBT
  • this evidence shows that drug treatments can be an effective treatment for most people with OCD
• Drug therapy for OCD: strength

  • Cost-effective and non-disruptive
  • Cheap compared to psychological therapy - good value for NHS and drugs don't disrupt patients' lives. They can also manage/reduce symptoms and allow patients to work which benefits the economy
  • this shows that they are an appropriate treatment for patients and doctors
• Drug therapy for OCD: Limitation

  • drugs can have side effects
  • SSRIs: indigestion and blurred vision, although usually temporary
  • SNRIs: have more serious side effects. e.g. 10% of patients experience tremors and weight gain
  • this means that the treatment is not appropriate for all patients and the effectiveness is reduced because people stop taking the medication
• Drug therapy for OCD: Limitations

  • treats symptoms not causes
  • if some cases of OCD are the response to a traumatic life event, drug therapy may treat symptoms, not the cause. To come to terms with the trauma, the patient may need psychological therapy
  • this means that drug therapy alone may not be an appropriate treatment for all cases of OCD