biological approach to treating OCD

• nestadt et al 2000

  • genetics play a role in disorders
  • using evidence from twin studies and family studies they showed close relatives are more likely to have the disorder than more distant relatives
  • people with first degree relatives with ocd are 5x more likely to develop it than the general population
  • BUT ... do relatives just learn from eachother rather than it just being genetic?
• twin study analysis


  • identical twins are 2x as likely to develop ocd if their co twin had it compared to non identical
  • concordance rate (if one has it the other had it) for identical = 68%, for non identical = 31%
  • if there was no genetic element we would expect no difference between identical and non identical twins
  • BUT ... if ocd was completely genetic, then concordance for identical twins would be 100%
• candidate genes


  • have been implicated in develpoment of ocd
  • SERT gene - regulates serotonin, neurotransmitter that transmits mood related information across synapses
  • COMT gene - regulates dopamine, effects motivation and drive
  • mutations in these genes have been linked to ocd
• basal ganglia - rapport and wise 


  • has been implicated
  • responsible for innate psychomotor functions eg. survival, food
  • the hypersensitivity can lead to repetitive motor behaviours seen in ocd like repetitive washing, cleaning, checking
• orbitofrontal cortex and the thalamus


  in ocd both are belived to be overactive

  orbifrontal cortex

  function - decision making and worry about social and other behaviour

  when overactive - increased anxiety and increased planning to avoid anxiety

  thalamus

  function - cleaning, checking, other safety behaviours

  when overactive - increased motivation to clean and check for safety

  if thalamus was overactive the orbitofrontal cortex would be too as a result
• genetic explanations - disadvantages

  • family studies could also be sued to explain environmental influences
  • close relatives of ocd sufferers may have observed and imitated behaviour - social learning
  • its difficult to untangle the effects of environment and genetic factors - nature vs nurture
• candidate genes - disadvantages

  • there are too many genes involved - over 200 (polygenic)
  • psychologists have not been successful at pinning down all the genes involved
  • each genetic variation only increases the risk of ocd by a fraction - no real predictive power (cannot be used for genetics)
• environmental factors - disadvantages

  • diathesis stress model
  • cromer 2007 - over half ocd patients in the sample had a traumatic event in the past and the ocd was more sever in those with more than one trauma
  • this means it may be more productive to focus on environmental causes as it seems that not all ocd is entirely genetic in origin
• neurotransmitters - disadvantages

  • drugs are not completely effective - can sometimes take weeks for brain / mood to change
  • just because administering SSRIs decreases ocd symptoms doesn't mean this was the cause in the first place
  • theres a time delay between taking drugs to target one condition and any improvement being made yet the chemical imbalance is addressed in hours
• areas of the brain - disadvantages

  • compulsions may be explained by the structural abnormality of basal ganglia but not necessarily the obsessional thoughts
  • inconsistencies in research as no system has found that it always plays a role in ocd
  • do neural changes cause ocd or does ocd cause changes in the brain? cause and effect issue
• interactionist approach - pauls et al


  there is a much higher percentage of ocd sufferers in relatives of patients with ocd than in the control group without ocd

  however...

  • its recognised not everyone in a given family gets ocd so there must be additional factors
  • diathesis stress model - people gain a vulnerability to ocd through genes / biological factors but an environmental stressor is also required. a stressful event, eg. bereavement
• drug therapy


  assumes there is a chemical imbalance in the brain

  this can be corrected by drugs which can either increase or decrease levels of neurotransmitters in the brain
• SSRI (selective serotonin reuptake inhibitors) 


  • involved in transmission of mood related info
  • standard treatment for ocd
  • increase certain neurotransmitters in the brain by preventing the reabsorption of serotonin
  • this increases its levels in the synapse and thus continues to stimulate the post synaptic neuron
  • this should lead to improving of symptoms as more and more gets released and builds up so the brain can return to effective communication
• combining SSRIs with other treatment 


  • drugs are often used alongside CBT
  • drugs reduce emotional symptoms like anxiety / depression, meaning patient can engage more effectively with CBT
  • some repond best to CBT alone without need for medication
• alternatives to SSRIs 


  • if an SSRI isnt effective after 3-4 months, dose can be increased or can be combined with other drugs
  • all patients respond differently
  • tricyclics - more side effects
  • SNRIs - increased serotonin noradrenaline levels
• drug therapy is effective

  • clear research showing SSRIs are effective in reducing OCD symptoms
  • soomro 2009 - better than placebo up to 3 months after treatment
  • little evidence on long term effectiveness
• drugs are cost effective and non disruptive 


  • cheap in comparison to psychological treatments and undisruptive to peoples lives
• drugs can have side effects


  • significant minority dont have benefits and have side effects like weight gain, dry mouth, loss of memory
  • coming off a drug is a slow process - has to be done gradually over 6 months
  • only treats symptoms and not the cause - many patients relapse once the medication is stopped
• unreliable evidence for drug treatments 


  • if drug companies sponsor the research they may decide to suppress results that dont support the drug theyre marketing
  • many drug companies dont publish all of their results and may be suppressing evidence
  • suggests the data marketing effectiveness may not be trustworthy
• some cases of OCD follow trauma


  • it is belived that OCD can have different causes
  • cases of OCD with no family history but caused by a relevant life event should be treated differently as those caused by family history and no trauma
  • for these cases drugs may not be appropriate
• fineberg et al 2007 


  • assessing efficiacy of escitalopram as a biological treatment for OCD
  • researched compared the impact of drug escitalopram and placeobo on symptoms of 320 people with OCD
  • Ps randomly allocated (ensures spread of symptoms, not like unreliable evidence) to recive either placebo or escitalopram, on a double blind basis (prevents bias)
  • after 24 weeks 52% of placebo group and 23% of escitalopram group reported recurrence of OCD symptoms