OCD

• OCD is characterised by?

  the presence of persistent obsessions and compulsions
• what are obsessions

  recurring persistent thoughts or images that are intrusive and cause high levels of anxiety
• what are compulsions

  repetitive behaviours (hand washing, touching something specific, counting)

  They are relief for the obsessions
• What is the criteria for a diagnosis of ocd?

  1. Recognise O/C are excessive and unreasonable
  2. take up more than 1 hour a day
  3. interferes with aspects of life such as jobs, school or relationships
• Measures of OCD:

  • Maudsley obsessional compulsive inventory (MOCI)
  • Yale Brown OC scale (YBCOS)
• Maudsley Obsessional Compulsive inventory

  • a short assessment tool
  • contains 30 items that score either true or false
  • assesses symptoms related to checking, washing, slowness, doubting
  • takes 5 mins to complete
  • produces a score range (0-30)
  • Examples: 'I frequently have to check things several times' 'I am not unduly concerned about germs and diseases (washing)
• Yale - Brown OC scale

  • Another validated measure of OCD 
  • Used as a semi-structured interview and there are 2 parts 
  • Part 1: The symptom checklist gives 67 symptoms of OCD 
  • The interviewer notes whether each symptom is current, past or absent  
  • The list of symptoms is divided into groups such as aggressive obsessions, sexual obsessions, contamination obsessions, ordering obsessions  
• Part 2 of YBCOS

  • Part 2: 10 items 5 about obsessions and 5 about compulsions
  • individual rates the amount of time they spend on obsessions, how hard they are to resist and how much distress they cause
  • scores range from 0 - 40 (scores over 16 are considered in clinical range for OCD)
• Biological - Biochemical Explanations

  1. Oxytocin
  2. Serotonin + dopamine
  3. Genetics
• Oxytocin Explanation - in favour

  • love hormone (enhances trust + attachment but also increases distrust + fear of certain stimuli)
  • Researchers have tested whether SSRIs affect oxytocin – main result was that levels of oxytocin positively correlated with OCD symptoms - those with early onset OCD had highest levels
• Oxytocin explanation - not in favour

  • In contrast DEN BOER AND WESTENBERG found no evidence of a link between oxytocin and OCD – they used a double-blind, placebo-controlled study by 12 of the patients with OCD, half were given syntocinon (synthetic oxytocin) through a daily nasal spray and half were given a placebo ​- no reduction in obsessions or compulsions
• Dopamine explanation- high levels


  Research shows that those with OCD tend to have abnormally high levels of dopamine – SZECHTMAN shows that if you increase dopamine levels in rats, they will show repetitive movements that reflect the compulsive behaviours of individuals with ocd
• Serotonin Explanation - low levels


  Research shows that individuals with OCD have lower than normal levels of serotonin in their brains. This is supported by evidence that shows anti-depressants that work specifically on increasing levels of serotonin ​
• Genetic Explanation

  • Meta-analysis of 14 twin studies found on average MZ (identical) twins 2x more likely to develop the disorder than DZ twins​
  • MATTHEISEN: conducted a large-scale study involving 1406 patients with OCD and other members of the general population
  • He analysed and identified genes that may be linked to OCD symptoms ​

  The gene PTPRD was implicated along with SLITRK3 both of which interact to regulate synapses in the brain 
• Cognitive - thinking errors


  COGNITIVE EXPLANATION considers that obsessive thinking is based on faulty reasoning ​

  MOWRERS 2-FACTOR THEORY:  ​

  1. obsessions come to evoke anxiety through classical conditioning  ​

  2. anxiety is reduced through compulsions which are therefore reinforced (operant conditioning )

  e.g hand washing becomes a negative reinforcer as it has relieved something unpleasant but at the same time a positive reinforcer as the person is 'rewarded' by knowing they have clean hands = shapes compulsive behaviours as they become learned
• Psychodynamic explanation - unconscious beliefs and desires


  Theorists claim that symptoms of ocd appear as a result of internal conflict between the id and the ego ​

  • suggested conflict arises in the anal stage of psychosexual development
  • Process involves tension between children and their parents who wish to control when the child uses the loo, against the child's wishes.
  • The obsessive thoughts that come from the id disturb the rational part of the self (ego) to the extent that it may lead to compulsive cleaning and tidying later in life, in order to deal with the earlier childhood trauma ​
• Biological Treatments - SSRIs

  OCD can be treated with a range of different drug therapies including antidepressants and anti-anxiety medication 

  Most used: SSRIs – they work by blocking the serotonin from being reabsorbed once a message has been passed from one neuron to another, meaning that the serotonin levels remain higher 

  • The effect of SSRIs is that they reduce the severity of obsessive-compulsions symptoms as they seem to lessen the anxiety associated with the disorder
• Evidence for SSRIs - study done by Soomro

  • Meta-analysis reviewed the results of 17 studies (3097) ppts which compared the effectiveness of SSRIs with placebos  
  • Used Y-BCOS to measure OCD symptoms  
  • In all studies SSRIs as a group were more effective than placebos at reducing OCD symptoms 6-13 weeks post treatment  60% of patients with OCD improve with medication but a high dose needs to be taken for at least 12 weeks  

  HOWEVER, it is not a cure as 75% of patients relapse in the months following stopping the drug  
• Psychological: Exposure and Response therapy - A FORM OF CBT  

  • Individuals are exposed to stimuli that provoke their obsessions and the associated distress while at the same time they are helped to prevent their compulsive behaviour  
  • The key is to prevent the compulsive behaviour as a response to the obsessive thought
  • This helps the individual to learn that the uncomfortable feelings will eventually go away even without performing a compulsive behaviour