OCD

• Characteristics of OCD

  Behavioural = compulsions, avoidance

  Emotional = anxiety and distress, accompanying depression, guilt and disgust

  Cognitive = obsessive thoughts, cognitive coping strategies, insight into excessive anxiety
• Genetic Explanations of OCD


  Lewis observed that of his OCD patients:

  • 37% had parents with OCD
  • 21% had siblings with OCD

  Suggests that the genetic vulnerability to develop OCD is inherited

  Candidate Genes - create a vulnerability for OCD, involved with regulation and transmission of serotonin
• Genetic Explanations (2)

  Diathesis Stress Model = certain genes make people more likely to develop a disorder. Environmental stress is required to trigger the condition.

  OCD is polygenic meaning it is not caused by one gene but a combination of genetic variations (Taylor found 230 genes associated)
• Genetic Explanations (3)

  OCD is aetiologically heterogeneous meaning the origins vary from one person to another, different types of OCD may be the result of particular genetic variations.
• Neural Explanations of OCD

  The genes associated with OCD are likely to affect levels of key neurotransmitters and the structure of the brain

  Serotonin:

  • regulates mood, low levels mean this doesn't take place
  • low levels associated with OCD and other mental disorders
• Neural Explanations (2)


  Decision making systems in the brain:

  • OCD is associated with poor decision making
  • The frontal lobe is responsible for this, and impairment is associated with OCD
• Explaining OCD : Strength

  Nestadt et al reviewed twin studies and found concordance rates of 68% for MZ and 31% for DZ twins. This shows that there must be some genetic influence on the development of OCD.
• Explaining OCD : Strength

  Soomro et al reviewed 17 studies that compared SSRIs to placebos in the treatment of OCD. All the studies showed better outcomes for SSRIs than placebos. Provides external validity for neural explanations due to real-life applications.
• Explaining OCD : Weakness

  Environmental factors are overlooked, as seen in Nestadt's study where concordance rates were not 100%. Cromer et al found that over half the OCD clients in their sample had experienced a traumatic event in their past, suggesting a more holistic explanation could be appropriate.
• Treating OCD 


  Drug therapy aims to increase or decrease levels of neurotransmitters in the brain or to increase/decrease their activity. Low serotonin is associated with OCD so drugs work to increase serotonin levels.
• SSRIs

  Selective Serotonin Reuptake Inhibitors are a type of antidepressant that work by preventing the reabsorption of serotonin by the pre-synaptic neuron. The increased levels of serotonin in the synapse results in the continued stimulation of the post-synaptic neuron. This compensates for the lack of natural serotonin.

  Available as pills or liquid and takes 3-4 months of daily use to have an impact.
• Combining SSRIs

  Drugs are often used alongside to treat OCD, with drugs reducing emotional symptoms allowing more effective engagement to CBT.
• Alternatives to SSRIs


  Tricyclics:

  • Acts on variety of systems
  • More severe side effects, so used if SSRIs had no effect

  SNRIs:

  • Increase levels of serotonin and noradrenaline
• Treating OCD : Strength

  Soomro found in 17 studies SSRIs were more effective than placebos in every case, providing evidence for effectiveness.
• Treating OCD : Strength

  Drug treatments are cost-effective and non-disruptive to people's lives than attending therapy sessions that are long and costly.
• Treating OCD : Weakness

  There are severe side effects of SSRIs, like indigestion and blurred vision, that can be distressing. Tricyclics are more severe and include weight gain and heart related problems. Suggests some people have a reduced quality of life which may lead them to stop taking the drugs altogether.
• Treating OCD : Weakness


  Drug therapies treat the symptoms and not the cause, so that when someone stops taking the drugs, they are prone to relapse. Therefore, psychological treatments like CBT may be more effective long-term.