Biological - OCD

• What does OCD stand for?

  Obsessive Compulsive Disorder
• What is the 3rd symptom of OCD?

  Compulsions - which are repetitive actions that people feel urged to do, in order to reduce feelings of guilt and anxiety.
• What is the 1st symptom of OCD?

  Obsessions - disturbing, recurrent thoughts
• What is the 2nd symptom of OCD?

  guilt and anxiety - brought on by Obsessions
• What symptom of OCD is also referred to as a cognitive symptom?

  Obsession
• What symptom of OCD is also referred to as a behavioral symptom?

  Compulsions
• What symptom of OCD is also referred to as a emotional symptom?

  Guilt and anxiety
• What does the Orbitofrontal cortex do?

  It detects worrying stimuli and selects an appropriate action to deal with it. It then sends signals to parts of the brain that control movement.
• Region A is called the Basal Ganglia

  Region B is called the Orbitofrontal cortex
• The Basal Ganglia is known for monitoring the outcome of our actions and sends inhibitory signals back to the orbitofrontal cortex.
• According to the neutral explanation of OCD?

  Those with OCD have impaired communication between the basal ganglia and the orbitofrontal cortex and the signals sent between are much weaker than usual.
• When the signals sent from the basal ganglia to the orbitofrontal cortex are much weaker than usual, the orbitofrontal cortex is less inhibited than it should be and becomes hyperactive. (which generate symptoms of OCD)
• Statements surrounding serotonin.

  • When the basal Ganglia sends signals to the orbitofrontal cortex, serotonin is released into the orbitofrontal cortex.
  • Serotonin acts an inhibitory neurotransmitter in the orbitofrontal cortex.
• According to the biological explanation of OCD...

  People with OCD have lower levels of serotonin and have neurons that are more active in the orbitofrontal cortex.
• Support for the Neutral Explanation of OCD are case study's such as...

  Max et al. studied a girl who developed OCD after experiencing some brain damage - she had damaged her Basal Ganglia (MRI). This proved the disturbed communication between the basal ganglia and the orbitofrontal cortex causes OCD.
• Support for the Neutral Explanation of OCD are Brain Imaging studies such as...

  Saxena and Rauch’s (2000) study, where they reviewed brain imaging studies that compared the brain activity of adults who have OCD with the activity of that without. They found increased brain activity in the orbitofrontal cortex of adults with OCD compared to the controls. This suggest that hyperactivity is a cause of OCD.
• Limitations of the Neural Explanation of OCD?

  • The results of studies haven't always replicated and brain imaging studies can be inconsistent.
  • e.g. Aylward et al found no differences between the basal ganglia's of people with OCD and health controls. suggesting it may not be the only cause (opposing Max et al's theory)
• What does the genetic explanation of OCD say?

  We can inherit OCD from out parents

  Specific gene alleles can increase a person's risk of developing OCD
• Information of 'The SERT' Gene

  • The SERT gene produces re-uptake proteins
  • the SERT gene has been associated with OCD
  • The more re-uptake proteins that are produced, the less serotonin is available in the synapse.
• What does the long allele of the SERT gene do?

  It produces more re-uptake protein, meaning there is less serotonin available therefore causing less inhibition of neural activity. (related with OCD)
• What does the Short allele of the SERT gene do?

  It produces less re-uptake protein, meaning there is more serotonin available therefore causing more inhibition of neural activity. (not related with OCD)
• What is a concordance rate?

  A percentage of twins that both share the same trait
• Twin study: BILLET ET AL.

  Billet et al. conducted a review of twin studies, to assess genetic inheritance of OCD, he concluded that the larger difference in concordance rates between monozygotic and dizygotic twins indicated OCD is partially inherited.

  Monozygotic - 68%

  Dizygotic - 31%
• Nestadt et al. found that 12% of the experimental group has a relative who also has OCD. On the other hand, only 3% of the control group had a relative who had OCD. The researcher could conclude that of one person in a family has OCD, other members of the family are more likely to have OCD as well. The researcher could conclude that OCD is likely to be partially inherited, because of the difference in the number of family members with OCD between the experimental and control group.
• Hu et al. analysed the DNA of people with OCD, comparing them to a control group. Hu et al. concluded that carrying the long allele of the SERT gene led to an increased chance of developing OCD.
• One limitation of the Genetic Explanation of OCD

  Twin studies assume that monozygotic and dizygotic twins have the same amount of shared environment, when they might not.

  Concordance rates for OCD in monozygotic twins are likely to also be influenced by having more of a shared environment than dizygotic twins.
• According to the biological explanations of OCD, people with OCD have a hyperactive orbitofrontal cortex, and an underactive basal ganglia
• One treatment for OCD is...SSRIs

  SSRIs block serotonin reuptake, resulting in more serotonin being available at the synapse. SSRIs also increase inhibition of neural activity in the orbitofrontal cortex.
• What strength is there of the biological Treatment of OCD

  It is Effective with drug treatments (supported by SSRI cases) - Soomro et al.
• Soomro et al. reviewed 17 studies investigating the effectiveness of SSRIs.

  He found that 70% of patients treated with SSRIs experienced an improvement in symptoms. This supports the use of SSRIs to treat OCD.
• 2 Strengths of the biological treatment of OCD

  • The effectiveness supported by studies
  • Relatively cheap way to treat patients
• SSRIs work when they block the reuptake of serotonin. This leads to more serotonin being available being available at the synapse. This creates a decrease in neural activity in the orbitofrontal cortex.
• One limitation of the biological treatments is that they can cause unwanted side effects. This is due to drugs not just affecting the areas of the brain that are targeted for treatment.
• Another limitation of the biological treatments of OCD....

  Patients have to take the drug indefinitely - patients have found that if they stop taking SSRIs their symptoms quickly come back which is called relapse.
• The 3rd limitation of biological treatments of OCD is.....

  Biological treatments do not consider cognitive factors of OCD. Therefore the best result may be being used alongside cognitive treatments.