OCD

• Biological approach

  Abnormal behaviour is caused by something physical happening in the body, which may be the result of genes
• Genetic explanations

  • Genes may create a vulnerability (risk of developing) to OCD
  • OCD runs in families
  • Diathesis-stress model suggests vulnerability plus environment may trigger OCD
  • Many candidate genes involved, OCD is polygenic
  • OCD is aetiologically heterogeneous
• Evidence for genetic basis

  • 68% of identical twins both diagnosed with OCD, compared to 31% of non-identical twins
• There are too many candidate genes for OCD- potentially hundreds, making a definitive genetic cause unlikely</b>
• Environment is more important than biology in developing OCD - OCD was more severe in patients who had experienced traumatic events
• Neural explanations

  • Low serotonin levels lead to impaired mood-relevant information transmission and obsessive thoughts
  • Abnormal frontal lobe functioning leads to impaired decision-making
  • Abnormal left parahippocampal gyrus functioning leads to more processing of unpleasant emotions
• Increasing serotonin levels reduces OCD symptoms, suggesting serotonin has a role
• Lack of understanding of neural mechanisms involved, and cause-effect relationship not known
• Drug therapies

  Affect neurotransmitter activity in the brain by affecting synaptic activity
• SSRIs

  • Block reuptake of serotonin, leaving more in the synapse
  • Take 3-4 months to show benefits
  • Often combined with CBT
• Other drugs

  • Tricyclics
  • SNRIs
• SSRIs significantly better than placebos at reducing OCD symptoms
• Strengths of drug therapy

  • Easy and non-disruptive, suits any lifestyle
• Weaknesses of drug therapy

  • Side effects like indigestion, loss of sex drive, blurred vision, weight gain, aggression
• Obsessive-compulsive disorder (OCD)


  People experience thoughts and urges that are intrusive and unwanted (obsessions) and/or the need to engage in repetitive behaviours or mental acts (compulsions)
• Sufferers of OCD

  Often have obsessions and compulsions that are linked
• Example of OCD

  • A person has an extreme fear of catching an illness (obsession) and so spend hours each day washing their hands (compulsion)
• Obsessions


  • The cognitive aspect of OCD
  • Persistent, unintentional, and unwanted thoughts and urges that are highly intrusive, unpleasant, and distressing
  • Common obsessions include concerns about germs and contamination, doubts, order and symmetry, and urges
  • The person knows such thoughts and urges are irrational and tries to suppress or ignore them, but has an extremely difficult time doing so
• Compulsions

  • The behavioural aspect of OCD
  • Repetitive and ritualistic acts typically carried out to minimise the distress that obsessions trigger or to reduce the likelihood of a feared event
  • Include behaviours such as repeated and extensive hand washing, cleaning, checking, and ordering, as well as mental acts such as counting, praying, or reciting something
  • Not done out of pleasure and not connected in a realistic way to the source of the distress or feared event