explaining OCD

• behavioural characteristics of OCD:

  • compulsions - repetitive behaviours
  • avoidance - avoid situations that trigger anxiety
• emotional characteristics of OCD:

  • anxiety and distress
  • depression
  • guilt and disgust
• cognitive characteristics of OCD:

  • obsessive thoughts - recurring and unpleasant
  • cognitive coping strategies
  • insight into excessive anxiety - aware behaviour is irrational
• Lewis:

  • 37% had parents with OCD
  • 21% had siblings with OCD
  • suggests vulnerability is inherited
• diathesis stress model:

  • certain genes make people more likely to develop disorder
  • environmental stress is needed to trigger condition
• candidate genes:

  • genes that create vulnerability
  • some are involved in regulation and transmission of serotonin
• OCD is polygenic:

  • caused by a combination of genetic variation that increase vulnerability
  • Taylor - up to 230 genes associated with OCD
• OCD is aetiologically heterogeneous:

  • origins of OCD vary from person to person
  • one group may cause disorder, another group in another person
  • different types may be result of genetic variations
• neural explanations:

  • genes associated with OCD are likely to affect levels of neurotransmitters and structures of brain
• serotonin:

  • helps regulate mood
  • low levels = no transmission of mood relevant information
  • low levels associated with OCD and other disorders
• decision making in brain:

  • OCD associated with poor decision making
  • frontal lobe responsible for logical thinking + decision making
  • impairment of frontal lobe associated with OCD
• EVALUATION: research support for genetics

  • Nestadt et al - twin studies and concordance rates, 68% MZ twins, 31% DZ twins - more genetically related = more likely to develop
  • person with OCD family member = 4x more likely to develop compared to someone without
  • there must be some genetic influence on development of OCD
• EVALUATION - research support for neural

  • antidepressants working purely on serotonin effective in reducing symptoms
  • soomro et al - 17 study review, compared placebos to SSRIs in treatment - all studies showed better outcomes for SSRIs
  • provides support for role of neurochemistry, provides explanation with external validity due to real life applications
• EVALUATION: environmental risk factors

  • strong evidence for neural and genetic factors - doesnt appear entirely genetic in origin, concordance rates for MZ arent 100%
  • cromer et al - half of OCD clients experienced trauma, OCD more severe with more traumas
  • neural and genetic factors only provide partial explanation, more hollistic explanation more appropriate