OCD

• OCD


  A range of disorders, characterised by either obsessions, compultions or both
• OCD Examples

  • Trichotiyomania: compulsive hair pulling
  • Hoarding disorder
  • Exocoriation disorder
• OCD REMEMBER!


  • A compulsion is a behaviour
  • An obsession is a compulsion
• OCD: Behavioural characteristics

  • Compulsions
  • Repetition
  • They can reduce anxiety (short term)
  • Avoidance: attempting to reduce anxiety by keeping away from situations that trigger it
• OCD: Emotional characteristics

  • Anxiety and distress, unpleasant and overwhelming
  • Accompanying depression, low mood, lack of enjoyment
  • Guilt and disgust, at oneself or things around you
• OCD: Cognitive characteristics

  • Obsessive thoughts, vary
  • Mediation or praying to deal with thoughts
  • Insight into excessive anxiety (aware that their compulsions and obsessions are irrational)
  • Hypervigilant
• Biological approach to explaining OCD 


  Caused by faulty biological processes

  • Two main explanations: Genetic and Neural
• Genetic explanations


  • OCD is inherited from your parents
  • Heritable: There is a genetic component which increase an individual's genetic vulnerability to developing OCD
  • Candidate genes: Genes which, through research, have been implicated in the development of OCD
• Polygenic 


  OCD is polygenic: more than 1 gene has been identified in the onset of OCD
• The COMT gene


  Regulates the function of dopamine, mutated in individuals with OCD (Mutation: increased dopamine)
• The SERT gene


  Helps to transport serotonin, also mutated in individuals with OCD (mutation: decreased serotonin)
• Aetiologically Heterogeneous 


  Different combinations of genes are implicated in the disorder
• Investigation of OCD: Twin studies 


  Concordance rate:

  • Monozygotic twins share 100% of DNA whereas dizygotic twins share 50% of DNA
• Evaluation: Genetic explanation AO3

  Supporting evidence: Strength

  • Family/twin studies
  • Nestadt et al. 2010
  • Reviewed previous twin studies
  • Monozygotic OCD concordance: 68%
  • Dizygotic OCD concordance: 31%
  • There is a genetic component to the disorder
  • Research support

  COUNTER: Diathesis-stress model, flaws of using twin studies
• Diathesis-stress model 


  Suggests that people gain a vulnerability towards OCD through genes but an environmental stressor is also required
• Evaluation: Genetic Explanation AO3

  Too many candidate genes: Limitation

  • Too many genes involved
  • Psychologists have still not successfully pinned down every gene
  • Taylor (2013) -> Meta analysis (found around 230 genes implicated in developing OCD)
  • Each genetic variation only increases the risk of OCD by a fraction (little predictive power)
• Neural explanations


  Psychological characteristics are determined by behaviour of the nervous system, in particular the brain as well as individual neurons
• Neurotransmitters 


  These are chemical messangers that transmit nerve impluses from one cell across the synapse to another cell
• Serotonin


  Lower levels of serotonin found in OCD sufferers
• Dopamine 


  Levels are high in people with OCD
• Serotonin is a mood regulators and dopamine triggers your mind to believe you are going to receive a reward -> Dependancy
• The Worry circuit 


  • The orbitofrontal cortex: tell your body there is a danger
  • thalamus: What needs to occur to escape that danger
  • Caudate nucleus: bodyguard for thalamus (filter that blocks worry signals)
  • people with OCD have an unfunctional caudate nucleus, not able to filter messages
  • Overactive worry circuit
• The Neural explanation: Evaluations

  Research support: Strength

  • Antidepressants which contain serotonin reduce symptons of OCD
  • Proves that lower levels serotonin triggers OCD
• The Neural explanation: Evaluations

  Co-morbidity issues: Limitation

  • Yap et al (2012) -> depression is linked to a lack of serotonin
  • Serotonin disrupted because they are depressed (not suffering from OCD)
• The Neural explanation: Evaluations

  Correlation vs Causality: Limitation

  • Both OCD and neural abnormality may be influenced by a third factor
  • No established cause of explanation
• Drug therapy


  • most common biological therapy
  • this therapy assumes there is a chemical imbalance in the brain
  • This can be corrected by drugs, which increase or decrease the levels of neurotransmitters in the brain
• SSRIs


  • Selective Serotonin reuptake inhibitors
  • venting the reabsorption of serotonin
  • by preventing this reabsorption, SSRIs effectively increase its levels in the synapse and thus continue to stimulate the post synaptic neuron
  • Examples include Prozac and Paxil
• Combining SSRIs with other treatment

  • Drugs are often used alongside CBT
  • The drugs reduce the sufferers emotional symptoms
  • Patient can engage better/more effectively with CBT
• Alternative to SSRIs


  • SSRI not effective, dose can be increased after 3 or 4 months or combined with other drugs
  • Tricyclics -> same effect with more side effects
  • SNRIs -> increase levels of serotonin and noradrenaline
• Evaluations of treating OCD

  Effectiveness: Strength

  • Using placebo vs drugs, the drug is effective
  • Soomro et al. (2009) reviewed 17 studies of the use of SSRIs with OCD patients across different measures
  • Typically, symptoms decreased by 70%
  • More effective when paired with CBT

  COUNTER

  • Skapinakis et al. (2016) did a review
  • Findings: cognitive and behavioural techniques were more effective than SSRIs at treating OCD
  • Reduces validity
• Evaluations of treating OCD

  Side effects: Weakness

  • Common side effects of SSRIs are headaches, nausea, insomnia and reduced sex drive
  • Tricyclics: more serious, hallucinations, irregular heartbeat
  • Such factors may reduce effectiveness and cause people to stop taking the medication
• Evaluations of treating OCD

  Not a lasting cure: Limitation

  • Marina et al (2001) found that relapse is common
  • Turner et al. (2008) -> publication is biased towards studies that show a positive outcome
  • More research is funded by drug companies
  • Selective publication -> lead doctors to make inappropriate treatment decisions
  • Validity issues