biological approach explaining OCD

• AO1 genetic explanation

  • family studies have given support into the biological explanation of OCD
  • nestadt 2000
  • reviewed twin studies68% of MZ twins shared OCD 31% of DZ twins shared OCD 
  • marini 2012
  • family studies found that a person with a family member diagnosed with OCD IS 4x as likely to develop it 
  • therefore 
  • suggests that theres some genetic influence on the development of OCD
• AO1- brain structure

  • several regions in the frontal lobes have abnormal brain circuits in patients with OCD

  orbitofrontal cortex

  - region that converst sensory information into thoughts and actions

  - PET scans have found higher activity when carrying out activities that produce

  OCD symptoms 

  - heightened activity increases the conversion of sensory information to behaviours which results in compulsions
• more genetic explanations

  • identified specific candidate genes which are implicated in OCD
  • OCD is polygenic which means several genes are involved
  • taylor 2003
  • 230 genes are involved, different genetic variations contribute to the different types of OCD
  • COMT gene
  • COMT regulates dopamine 
  • higher levels of dopmaine are found in OCD patients, which may link this gene 
  • SERT gene 
  • lower levels of serotonin is associated with OCD and despression 
  • affects the transport of serotonin 
• AO1 the role of serotonin

  • low levels of serotonin explains cases of some OCD 
  • serotonin helps regulate mood 
• decision making systems

  • its associated with abnormal functioning of the lateral of the frontal lobes of the brain
  • the frontal lobe: responsible for logical thinking and making decisions
  • left parahippocampul gyrus: associated with processing unpleasant emotions, functions abnormally in OCD
• AO3 research support

  • nestadt 2010: reviewed twin studies, 68% of MZ twins shared OCD, 31% of DZ twins
  • nestadt 2000: proposes that individuals who have first degree relatives with OCD are 5x as likely to develop OCD, compared to members of the general population without a general link
  • research from family studies provide support for the genetic explanation for OCD, although it doesnt rule out other environmental factors playing a role
• AO3 environmental risk factors

  • genetic model ignores theres environmental risk factod
  • evidence: genetIc variation can make a person more or less vulnerable to OCD
  • OCD doesn't appear to be entirely from genetic origin, environmental risk factors trigger or increase the risk of developing OCD
  • cromer 2007: over 1/2 of OCD clients in their sample had experienced a traumatic event in their past
  • OCD is more severe with 1 or more traumas
  • genetic vulnerability only provides a partial explanation for OCD
• AO3 research support

  • antidepressants work purely on serotion, are effective in reducing OCD symptoms
  • which suggests serotonin is involved in OCD
  • OCD symptoms are known to form part of biological disorders which assumes the biological processes underlie OCD
  • which supports and suggests that biological factors are responsible for OCD
• AO3 brain structure

  • issue with understanding neural mechanisms involved with OCD
  • research identified other areas of the brain are involved with OCD
  • this means
  • theres no brain system which has constantly played a role in OCD
  • although, theres evidence of neurotransmitters and brain structures
  • theres no concluded cause and effect
• AO3 no unique neural system

  • many people with OCD also experience clinical depression, which is co morbidity
  • this depression involves disruption to the action of serotonin
  • this has logical problem when it comes to serotonin as a basis for OCD
  • it could be the serotonin activity is disrupted in many people with OCD, as they're depressed as well
  • this means that serotonin may not be relevant to OCD symptoms