OCD

• what is ocd


  obsessive compulsive disorder
• how many people suffer from ocd in the uk


  740,000
• what is a compulsion


  a behaviour
• what is an obsession


  something you think/cognitive
• behavioural characteristics of ocd


  -compulsions which are repetitive and people feel compelled to do them a lot, these also reduce anxiety temporarily

  -avoidance, eg of situations that trigger anxiety eg avoiding coming into contact with germs by excessive cleaning but this can impact daily life
• emotional characteristics of ocd


  -anxiety and distress

  -accompanying depression

  -guilt and disgust at the trigger or the self
• cognitive characteristics of ocd


  -obsessive thoughts

  -cognitive coping strategies such as praying but this could interrupt everyday life and seem abnormal to others
• whats the cycle of ocd


  obsessive thought

  anxiety

  compulsive behavior

  temporary relief
• how have scientists tried to understand ocd


  twin studies
• what are the 2 explanations for ocd


  -genetic

  -neural
• what are the two types of twin

  MZ- monozygotic, identical

  DZ- dizygotic, non-identical
• how many genes do MZ/DZ twins share


  MZ- 100%

  DZ- 50%
• why will twins share a similar environment/ nurture


  they grow up in the same family, household, area
• what is a concordant rate


  a measure of genetic similarity between two individuals or sets of individuals on a given trait usually expressed as a %
• what is a biological approach to ocd


  -twin and family studies

  -genes, the comt and sert gene
• evidence for ocd being genetic

  lewis (1936) examined ocd patients and found that 37% of OCD sufferers had parents with the disorder and 21% had OCD suffering siblings
• what is the COMT gene


  -COMT gene is associated with the production of COMT which regulates the neurotransmitter dopamine

  -a variation of the COMT gene results in higher levels of dopamine and this variation is more common in people who have ocd
• what is the SERT gene


  Linked to serotonin and effects the transport of serotonin

  -transportation issues cause lower levels of serotonin to be active within the brain and is associated with ocd and depression
• evaluation of genetic explanations (supporting)


  supported by family studies

  -nestadt et al found that people with a first-degree relative with OCD are up to 5x more likely to develop OCD over their lifetime compared to people without this link

  
  

  twin studies

  -nestadt et al found 68% of MZ twins shared OCD and 31% of DZ twins shared OCD

  -billett et al did a meta analysis of 14 twin studies and concluded that MZ twins had double the risk of developing OCD compared to DZ twins if one of the pair was found to have OCD
• evaluation of genetic explanations (against)


  environmental risk factors

  -concordance rates between MZ twins are not 100% so there must be external/environmental risk factors

  -however there is some correlation between MZ twins so it is suggested that genetics can make someone more vunerable to developing OCD

  -it has been found that over half of a studies OCD patients had a traumatic trigger event in their past

  -this suggests that environmental factors like traumatic events play a role in ocd developing

  
  

  this is called...diathesis-stress

  -having a genetic predisposition eg having a faulty COMP/SERT gene which then stresses/triggers cause to turn into OCD
• neural explanations for ocd


  role of serotonin

  - neurotransmitter serotonin is believed to play a role in ocd, it regulates mood and low levels are linked to ocd and depression

  
  

  brain structure

  - frontal lobes, the ORBITOFRONTAL CORTEX is a region which converts sensory info into thoughts and feelings, scans have shown this area to be more active in patients with OCD when they are asked to hold potential trigger items like a dirty bag (germs)

  -this increase in activity increases the conversion of sensory information to actions (behaviours) which lead to compulsions

  
  

  +

  
  

  -the BASAL GANGLIA is a cluster of neurons which is involved in multiple processes including the control of movement, people who develop brain injuries in this area often have ocd-like symptoms

  
  

  two process model
• evaluation of neural theories -positive


  role of serotonin:

  -SSRI's which affect serotonin have been shown to be effective in treating OCD which suggests serotonin plays a role in OCD

  -it is also supported by the evidence that high levels of the neurotransmitter dopamine has been associated with in particular the compulsive behaviors
• evaluation of neural theories -negative


  there are other structures in the brain that have been linked to ocd, not just the basal ganglia and orbito frontal cortex

  -this means that there is no brain system which has been consistently been linked to OCD which means that a cause and effect relationship cannot be concluded

  
  

  alternative explanations:

  two process model

  - classical conditioning where dirt is paired with anxiety which would be maintained by operant conditioning and negative reinforcement whereby the stimulus is avoided and the anxiety removed

  - this could result in an obsession forming which is linked to the development of a compulsion eg washing hands to reduce anxiety
• treatments of ocd, biological approach


  -drug therapies (ssri's, tricyclics, benzodiazapines)
• what are SSRI'S


  selective serotonin reuptake inhibitors

  - antidepressant drug

  - works on maintaining high levels of serotonin in the brain
• How do SSRI's work


  SSRI's prevent the reuptake of serotonin from the synapse which keeps the signal going for longer which causes higher serotonin levels
• what are tricyclics?


  alternatives to ssri's

  -also block the re-uptake transporter mechanism that reabsorb serotonin and noradrenalin

  -they target more than one neurotransmitter (advantage) but therefore have more side effects

  -mainly used as a second line of treatment if ssris dont work
• What are benzodiazepines?


  anti-anxiety drugs

  - slow down the activity of the central nervous system by enhancing the activity of the NT GABA which has a general inhabituary effect on many neurons in the brain
• why would drugs and cbt be used together


  drugs can stabilize the patient before cbt
• evaluation of drug treatment (positive)

  it is effective + works

  - proof: soomro - placebos vs SSRI's in 17 studies. The use of SSRI's with OCD patients found them to be more effective than placebos in reducing symptoms of OCD up to 3 months after treatment

  - symptoms declined for 70% of patients

  - was most effective when combined with a psychological therapy eg cbt

  
  

  it is cost effective

  -relatively cheap + less time consuming then CBT or talking therapies which need regular meetings and take effort from the client

  - drugs are easy and low effort and not intrusive into their lives
• evaluation of drug treatment (negative)


  have side effects

  -usually temporary , eg blurred vision, indigestion, loss of sex drive

  - more than 1 in 10 suffer from more serious side effects such as tremors, weight gain, erectile dysfunction, effects on heart + blood pressure

  
  

  unreliable evidence for drug treatments

  -publication bias

  -turner et al showed that there is a bias towards publication of studies which show positive outcomes of a drug which exaggerates its benefits

  
  

  some cases of ocd follow trauma

  -if ocd as a biological cause then drugs are an appropriate treatment

  -if ocd is a result of trauma then a behavioural or cognitive treatment such as cbt will be more appropriate