OCD

• What is OCD?

  A condition characterised by obsessions and/or compulsive behaviour. Obsessions are cognitive whereas compulsions are behavioural. ​
• What are obsessions?

  Cognitive; is something you think about
• What are compulsions?

  Behavioural; something you feel the need to do
• What percentage of OCD sufferers experience both obsessions and compulsions?

  70%

  
  

  20% experience just obsessions

  10% experience just compulsions
• Cognitive characteristics of OCD​

  - Obsessive Thoughts

  - Cognitive Coping Strategies

  - Insight into excessive anxiety
• Emotional characteristics of OCD

  - Anxiety and distress

  - Accompanying depression

  - Guilt and Disgust
• Behavioural characteristics of OCD

  - Repetitive Compulsions

  - Compulsions reducing anxiety e.g. excessive hand washing

  - Avoidance
• Genetic explanation of OCD


  particular genes are implicated in OCD. It is known as a polygenic which means there are multiple genes that might be involved with the development of OCD. ​

  
  

  Researchers have identified genes, which create this vulnerability for OCD, called candidate genes. S
• Two genes linked to OCD

  COMT and SERT gene
• What is the COMT gene?

  associated with the production and regulation of the neurotransmitter dopamine. ​

  
  

  One variation of the COMT gene results in higher levels of dopamine and this variation is more common in patients with OCD.

  ​
• What is the SERT gene?

  Linked to the neurotransmitter serotonin and affects the transport of the serotonin causing lower levels of serotonin which is also associated with OCD
• Lewis (1936) Genetic Explanation of OCD

  observed OCD in patients and found 37% have parents with OCD and 21% had siblings with OCD.

  This suggested that OCD can run in families.
• Billet et al (1998)

  MZ twins have a higher concordance rate for OCD than DZ twins. 68%MZ and DZ 31%.​
• What does Lewis' 1936 study imply?

  implies a genetic vulnerability/ predisposition rather than a guarantee.

  
  

  According to the diathesis- stress model certain genes leave some people more likely to develop mental disorder but is not certain.

  
  

  Instead, it is suggested that certain environments are most likely to trigger the development of the condition. ​
• Research to support polygenetics

  Taylor (2013) analysed findings of previous studies and found evidence of up to 230 different genes that may be involved with OCD development.

  
  

  These include the action of dopamine as well as serotonin both neurotransmitters believed to have a role in regulating mood.
• What do biological psychologist rely on for their studies on genetics?​

  Twin Studies/ Family Research
• Neural explanations for OCD​

  abnormal levels of neurotransmitters, in particular serotonin and dopamine, are implicated in OCD.​

  
  

  Also suggest that particular regions of the brain, in particular the basal ganglia and orbitofrontal cortex, are implicated in OCD.​
• Role of serotonin in OCD

  Serotonin regulates mood and lower levels of serotonin are associated with mood disorders, such as depression. ​
• Role of dopamine in OCD

  higher levels of dopamine being associated with some of the symptoms of OCD, in particular the compulsive behaviours.​
• Cromer et al (1998)


  reports serotonin and dopamine are linked to these regions of the brain (basal ganglia of OFC). ​
• Basal Ganglia Role

  Distributes serotonin and controls emotional and cognitive functions
• Orbitofrontal Cortex Role

  a region which converts sensory information into thoughts and actions.

  
  

  Responsible for anxiety ​
• Caudate nucleus

  acts as a filter suppresses messages from OFC​
• Thalamus

  responsible for safety behaviour​
• What occurs in a person without OCD in the brain?

  OFC sends message- eg touching sticky table ​

  
  

  Caudate nucleus- will supress message from OFC​

  
  

  Thalamus- only responds to major worry
• What occurs in a person with OCD in the brain?

  OCF sends message- touching sticky table ​

  
  

  Caudate nucleus- damaged and unable to supress or filter​

  
  

  Thalamus- responds to every message ​

  
  

  This continues to happen over and over again
• What do biological treatments for OCD aim to restore?

  biological imbalances, such as too little serotonin
• What is an SSRI

  selective serotonin re-uptake inhibitors) are a type of anti-depressant drug, which include drugs like Prozac.​
• How are neurotransmitters different from impulses?

  The impulses send signals from the body to the brain; (electrical)​

  
  

  Neurotransmitters send signals from the brain to the body. (chemical)​
• How do SSRI's work?

  SSRIs work by blocking (“inhibiting”) reuptake, meaning more serotonin is available to pass further messages between nearby nerve cells, which increases serotonin levels in the brain
• Combining SSRI's with other treatments

  Drugs are normally used in combination with other therapies such as CBT (cognitive behavioural therapy) to treat OCD. ​

  
  

  The drugs reduce the emotional symptoms such as anxiety and depression
• Alternatives to SSRI's

  Tricyclics- older type of anti-depressant which acts on various systems including the serotonin system where it has the same effect as SSRI ​

  
  

  SNRI's (serotonin -noradrenaline reuptake inhibitors)
• Disadvantage of Tricyclics

  people have extreme side effects to this ​
• Anti-Anxiety Drugs

  Benzodiazepines (BZs) such as Valium work by enhancing the action of the neurotransmitter GABA (gamma-aminobutyric acid).

  GABA tells neurons in the brain to ‘slow down’
• OCD treatment strengths

  • Evidence of Effectiveness, although drug therapy doesn't 'cure' OCD, it allows for a significant improvement
  • Drug therapy is cost-effective as they are cheaper than other psychological treatments
  • Drug therapy is non-disruptive to people's lives as they do not have to give up time to attend therapy.
  • Greist et al. (1995) conducted a meta-analysis where they reviewed placebo-controlled trials of the effects of 4 drugs on OCD. found all 4 drugs were significantly more effective than placebo
• OCD treatment weaknesses

  •Side effects: With SSRIs, these side

  effects can include; blurred vision, loss of sexual appetite, irritability, indigestion, and sleep pattern disruption.

  
  

  • High relapse rates once patients stop taking the drug.

  
  

  • Simpson (2004) found that 45% of cases in 12 weeks relapsed, compared to only 12% of patients who had CBT. This suggests, that drug therapy does not treat OCD.

  
  

  • Publication bias: Goldacre (2013) drug companies sponsor the drug trials they publish so only positive outcomes may be published