OCD-biological

• ocd- obsessive compulsive disorder
• tricyclic antidepressants are older drugs which have more side effects than SSRIs but they work on both serotonin and noradrenaline
• tricyclic antidepressants (TCAs) work by blocking the reuptake of both norepinephrine and serotonin
• OCD is thought to be caused by too much dopamine and not enough serotonin
• OCD is treated with SSRIs SNRIs or tricyclics
• Obsessive-compulsive disorder (OCD)

  A mental disorder characterized by obsessions and compulsions
• Most people with OCD experience obsessions and compulsions that are linked to each other
• Obsessions and compulsions in OCD

  • Obsession: Worrying about catching germs

  Compulsion: Excessive hand-washing
• OCD

  • Has two parts: 1) Obsessions (cognitive aspect) and 2) Compulsions (behavioural aspect)
• Obsessions

  Intrusive and persistent thoughts, images and impulses that cause distress
• Compulsions

  Repetitive physical or mental actions meant to reduce anxiety or prevent a feared situation
• The DSM states that the obsessions or compulsions must last at least 1 hour each day to indicate a clinical case of OCD
• Another indication of OCD is when the obsessions and compulsions interfere with a person's ability to maintain relationships, hold a job, or participate in social activities
• Common types of OCD behaviours

  • Checking

  Contamination

  Hoarding

  Symmetry and orderliness
• OCD affects about 2% of the world's population
• OCD typically develops in late teens or early 20s, and occurs equally in men and women across all ethnic groups
• The biological approach assumes psychological disorders are physical illnesses with physical causes
• Biological explanations for OCD

  • Genetic factors
  • Biochemical factors
  • Neurological factors
• Twin studies have shown that genetics have at least some effect on the likelihood of developing OCD
• PET scans have shown the levels of the neurotransmitter serotonin are lower in OCD sufferers
• PET scans have found the abnormality in the basal ganglia within the brain may be linked to OCD
• Strengths of the biological approach to OCD

  • It has a scientific basis in biology - there's evidence that low serotonin and damage to the basal ganglia correlate with cases of OCD, though this doesn't necessarily show a causal relationship
  • Twin studies have shown that genetics have at least some effect on the likelihood of developing OCD
  • It can be seen as ethical - people aren't blamed for their disorders, they just have an illness
• Weaknesses of the biological approach to OCD

  • The explanation doesn't take into account the effect of the environment, family, childhood experiences or social influences - psychologists taking other approaches consider these sorts of things important factors
  • Biological therapies raise ethical concerns - drugs can produce addiction and may only suppress symptoms rather than cure the disorder
• Biological treatment for OCD

  1. Drug therapy using selective serotonin reuptake inhibitors (SSRIs) to increase serotonin levels

  2. SSRIs prevent the reuptake of serotonin in the synaptic cleft, meaning more serotonin is available to the next neuron
• Advantages of SSRI treatment for OCD

  • Several researchers have found SSRIs to be effective in treating OCD
  • Research has found that using other antidepressants that don't affect serotonin levels is ineffective at reducing OCD symptoms
• Disadvantages of SSRI treatment for OCD

  • Up to 50% of patients with OCD don't experience any improvement in their symptoms when taking SSRIs
  • Out of those that do improve, up to 90% have a relapse when they stop taking them
  • SSRIs have to be taken for several weeks before the patient experiences an improvement in their symptoms
  • Side effects of using these types of drugs include nausea and headaches, and sometimes increased levels of anxiety, which can cause people to stop taking their medication
• Behavioural symtpoms of ocd- avoidance, compulsions
• Cognitive symptoms of OCD- obsessions, intrusive thoughts
• Emotional symptoms of ocd- anxiety, depression, anger, guilt
• Characteristics of OCD


  • Emotional: Anxiety and distress, Accompanied with depression, Guilt and disgust (often at intrusive thoughts or at germs/dirt etc.), Shame
  • Behavioural: Repetitive compulsions, Compulsive behaviours or compulsive checking done to reduce anxiety, Avoidance – staying away from situations that would trigger their anxiety. This can interfere with their life.
  • Cognitive: Obsessive thoughts: impulses, ideas, images or doubts – they are uncontrollable, Cognitive coping strategies – e.g., praying or meditation but this may occur at an abnormal frequency, Aware that obsessions and compulsions are not rational but still are hypervigilant and on edge about potential disasters
• Genetic approach to OCD

  Genes can lead to an increased likelihood of a condition being developed, but do not automatically make it certain. It can be triggered by a stressor (Diathesis-stress model)
• Concordance rates


  A measure of genetic similarity. The higher the concordance rate, the higher the genetic similarity.
• Concordance rates for OCD

  • Lewis (1936) - 37% of his patients with OCD had parents with OCD, 21% had siblings with OCD

  Nestadt (2000) - 11.7% concordance rate between Ps with OCD and first degree relatives compared to 2.7% with the general population

  Miguel (2005) - 53-87% concordance rate with monozygotic twins compared to 22-47% with dizygotic wins
• Polygenic


  Determined by a group of genes that work together as one unit. OCD is polygenic - it is caused by a combination of genetic variations that together significantly increase vulnerability.
• Aetiologically heterogenous


  The origins are different within different people. The genes that cause OCD can be different in different people.
• Diathesis-stress model


  Genes can lead to an increased likelihood of a condition being developed, but do not automatically make it certain. It can be triggered by a stressor.
• 45 word summary: Genetic factors play a key role in OCD, with candidate genes like COMT, SERT and 5HT1-D beta linked to neurotransmitter imbalances. Concordance rates are higher in twins, and OCD is polygenic and aetiologically heterogenous, with a diathesis-stress model explaining development.
• The left parahippocampal gyrus is associated with processing unpleasant emotions. In people with OCD, there has been evidence that the left parahippocampal gyrus functions abnormally, explaining the distress, fear, disgust, or anxiety involved in their intrusive thoughts.
• The basal ganglia has lots of jobs including the coordination of movement. Hyperactivity in the basal ganglia is linked to compulsive repetitive actions.
• Strengths of the biological approach to OCD

  • Lots of evidence for a genetic cause for OCD through twin and family studies

  Animal studies have provided a lot of evidence for the link between genetics and OCD