The Biological Approach and OCD

• OCD definition


  • OCD (Obsessive Compulsive Disorder) is a serious anxiety related condition
  • Individuals experience frequent, intrusive and unpleasant obsessional thoughts
  • These are followed by repetitive behaviours that seek to reduce the anxiety but only provide temporary relief
• Emotional characteristics of OCD

  • Unpleasant emotions (anxiety and distress)
  • Depression and low mood (lack of enjoyment) - compulsions bring temporary relief
  • Guilt, self-reproach/disgust
• Behavioural characteristics of OCD

  • Compulsive behaviours: Repetitive compulsions such as hand washing or checking, helps to manage the anxiety produced by obsessive thoughts and are often irrational and excessive
  • Avoidance: Keeping away from situations that trigger it which interferes with normal life
• Cognitive characteristics of OCD

  • Obsessive thoughts - recurrent and unpleasant - they are unable to resist them
  • Cognitive coping strategies: praying, counting or meditating
  • Awareness that obsessions are not rational
• Genetic Explanations of OCD - COMT gene

  • Tukel et al found that lower levels of activity of the COMT gene lead to higher levels of dopamine
  • Higher levels of dopamine is associated with stereotyped movements which manifest themselves as compulsions in OCD
• Genetic Explanations of OCD - SERT gene

  • Involved in the transport of serotonin which is associated with OCD and depression
  • Ozaki et al found evidence of two unrelated families with mutations of this gene where 6 of the 7 family members had OCD
• Genetic Explanations of OCD - Polygenetic


  • Not caused by a single gene
  • Taylor analysed findings from previous studies and found 230 genes may be involved in OCD
  • Genes studied in relation to OCD have been associated with the action of dopamine and serotonin which both have a role in regulating mood
• Genetic Explanations of OCD - Individual vulnerability

  • Lewis observed that of his OCD patients 37% had parents with OCD and 21% had siblings with OCD
  • Suggests OCD runs in families, although it is ‘genetic vulnerability’ that is passed on and not the certainty of OCD
• Genetic explanations of OCD - Supporting evidence AO3

  • Lewis et al observed that of his OCD patients 37% had parents with OCD and 21% had siblings with OCD - family studies provides support for genetic explanations of OCD
  • Further support comes from twin studies - Billet et al conducted a meta analysis of 14 twin studies investigating the genetic inheritance rate of OCD and concluded MZ twins had a double risk of developing OCD compared to DZ twins
• Genetic explanations of OCD

  • Research from twin studies have shown concordance rates are never 100%
  • Suggests there are also environmental risk factors and OCD does not appear entirely due to genetic origins
  • Cromer et al found over half of OCD patients had traumatic life events in there past and OCD was more severe in those with more than one trauma
  • Means genetic vulnerability only provides a partial explanation for OCD
• Neural Explanations of OCD - Abnormal brain circuits

  • Evidence from PET scans that people with OCD have areas of abnormality within their brains
  • Orbitofrontal cortex (OFC) sends signals to the thalamus about potential ‘worries’ - usually these minor worries are suppressed by the caudate nucleus
  • However if the caudate nucleus is damaged the worry is not suppressed and the thalamus is alerted and confirms the worry to the OFC
• Neural Explanations of OCD - Neurotransmitters

  • Serotonin is plays a role in regulating mood, if a person has low levels of serotonin, the person can have low moods and other mental processes are often affected
  • The reduction of serotonin can explain some cases of OCD
  • Dopamine levels are thought to be abnormally high in people who suffer from OCD
• Neural Explanations of OCD - Supporting Evidence AO3

  • PET scans have shown hyperactivity in the OFC when sufferers are exposed to a stimulus (Baxter)
  • Support from biological treatment such as anti depressants help increase the levels of serotonin
  • These drugs are effective in reducing the symptoms of OCD and provide support for a neural explanation of OCD
• Neural Explanations of OCD - Unclear explanation AO3

  • Unclear which neural mechanisms are involved in OCD
  • Despite research indicated the basal ganglia and OFC are involved in OCD other research has identified that other brain systems may be involved but no system is clearly identified that plays a role in OCD ex. frontal lateral lobes
  • No consistency which brain system has a role therefore there is a problem in establishing cause and effect since is not certain if OCD causes biological abnormalities or vice versa
• What are anti-anxiety drugs used for?

  They are used to treat anxiety disorders and symptoms of OCD.
• What are BZs and provide examples?

  • BZs are a type of tranquillisers.
  • Examples include:
  • Valium
  • Diazepam
• What is the role of GABA in the body?

  GABA is a neurotransmitter and is the body’s natural form of anxiety relief.
• How does GABA affect patients with OCD?

  It calms down the mind of patients with obsessive thoughts.
• How BZs work


  • BZs work by enhancing the action of GABA
  • GABA tells neurons in the brain to ‘slow down’ and ‘stop firing’ - less synaptic chemicals released
  • Around 40% of neurons respond to GABA
  • BZs have general quieting influence on the brain and consequently reduce anxiety and levels of serotonin which is experienced as a result of the obsessive thoughts
  • Also decreases heart and respiration rates to reduce levels of anxiety
• What are anti-depressants most commonly used to treat?

  Depression
• What is an example of an SSRI?

  Prozac
• Why do low levels of serotonin occur in the nervous system?

  Serotonin is reabsorbed into the nerve ending before it can move on to the next neuron
• How prozac works


  • When serotonin is released from the pre-synaptic neuron it travels to the receptor sites on the post-synaptic neuron
  • Serotonin which is not absorbed into the post-synaptic neuron is reabsorbed into the pre-synaptic neuron
  • SSRIs increase the levels of serotonin by preventing it from being reabsorbed and increases levels of serotonin
  • Improves mood and reduces anxiety experienced by OCD patients
• How does the reabsorption of serotonin affect its levels in the nervous system?

  It leads to low levels of serotonin available for neurotransmission
• Drug Therapy - Effective AO3

  • Soomro et al reviewed studies that compared SSRIs to placebos in the treatment of OCD and concluded that all 17 studies reviewed showed significantly better results for SSRIs
  • Effectiveness is greater when combined with psychological treatment ex. CBT
  • Symptoms decline for around 70% taking SSRIs
  • Other drug treatments are available for those who don’t respond
  • This is a strength because it supports biological treatments as SSRIs are an effective therapy that can improve people’s quality of life and has empirical support for effectiveness
• Drug Therapy - Cost-effective and non-disruptive

  • Good value for the NHS compared to psychological treatment
  • Non-disruptive to patients’ everyday lives - this is beneficial because they can take drugs until symptoms decline and not engage with hard work of psychological therapy
  • This is a strength as they are an appropriate treatment for most sufferers
• Drug Therapy - Side effects


  • Drugs can have temporary side effects like indigestion
  • May reduce effectiveness because people stop taking them
  • This is a weakness as SSRIs may not be the most appropriate or effective treatment for sufferers who respond with negative side effects to the treatment