A03

• One weakness of genetic explanations is that there are too many candidate genes involved in OCD.  

  • Although these explanations suggest that OCD is largely under genetic control, psychologists have been much less successful at pinning down all the genes involved.
  • One reason for this is because it appears that several genes are involved and that each genetic variation only increases the risk of OCD by a fraction. 
  • this means we cannot rely on genetic explanation alone
• One weakness of genetic explanations for OCD is that they fail to consider the influence of environment.  

  • It seems that environmental factors can also trigger or increase the risk of developing OCD (diathesis-stress model).
  • For example, Cromer at al. (2007) found that over half the OCD patients in their sample had a traumatic event in their past, and that OCD was more severe in those with more than one trauma.  
  • This suggest that OCD cannot be entirely genetic in origin, at least not in all cases.
• One strength of neural explanations is that they have informed biological treatments for OCD.  

  • Some antidepressants work purely on the serotonin system, increasing levels of this neurotransmitter. 
  • This suggests that if increasing serotonin levels treat OCD, serotonin must be involved, thus showing support for neural explanations.
• One weakness of neural explanations is that serotonin- OCD link may simply be comorbidity with depression.  

  • Many people who have OCD become depressed or have depression. Having two disorders is called co-morbidity. This depression probably involves disruption to the serotoninergic system in the brain.
  • suggesting serotonin levels are disrupted due to patients suffering from depression as well
• This suggests

  • there is a difficulty in separating the neural influences between different disorders and as such we cannot be confident in assuming serotonin is a cause of OCD.
• One weakness is that we cannot assume serotonin is definitely a cause of OCD.

  • There is evidence to suggest that various neurotransmitters and structures of the brain do not function normally in patients with OCD.
  • However, this is not the same as saying that this abnormal functioning causes OCD.
  • These biological abnormalities could be a result of OCD rather than its cause.  
• This shows

  • we cannot establish causality and we may be treating symptoms rather than causes of OCD