Biological explanation

• OCD is an anxiety disorder with reoccuring, uncontrollable, intrusive and anxiety provoking thoughts, leading to a need to perform repetitive behaviour or mental act
• Characteristics- 

  Behavioural- compulsions, avoidance

  Emotional- anxiety, accompanying depression, guilt and disgust

  Cognitive- obsessive thoughts, cognitive coping strategies 
• genetic explanation- genes are involved in individuals vulnerability to OCD, Lewis observed that of his OCD patients, 37% had parents with OCD and 21% had siblings with OCD. This suggest OCD runs i the family but it’s like just the vulnerability is passed on, and an environmental experience triggers the event (diathesis-stress model)

  OCD is seen to be polygenic, its caused by more than 1 gene.

  Candidate genes (COMT and SERT gene) are believed to create vulnerability for OCD
• neural explanation -the genes associated with OCD are likely to affect key neurotransmitters. 

  serotonin is believed to help regulate mood, if a person as low serotonin levels, then normal transmission of mood relevant information doesn’t take place so they are likely to experience low moods. Some cases of OCD may be linked to the function of serotonin.

  impaired decisions making is associated with OCD, this may be linked to abnormal function of the frontal lobes as its responsible for logical thinking and decision making. 
• OCD cycle

  Obsessive thoughts lead to anxiety which leads to a compulsive behaviour to relieve anxiety. This gives temporary relief and a sense of control, and then obsessive thoughts start again.
• One strength of the genetic explanation is the supporting evidence

  There is evidence from a variety of sources, which strongly suggest that some people are vulnerable to OCD as a result of a genetic make up

  twin studies found that 68% of identical twins shared OCD, as opposed to 31% of non-identical twins

  Researchers found that a family member diagnosed with OCD is around four times as likely to develop it as someone without
• One limitation of the genetic model is there is also environmental risk factors

  There is evidence for the idea that genetic variation can make a person more or less vulnerable. However, OCD does not appear to be entirely genetic in origin and seems That environmental risk factors can also trigger or increase the risk of developing OCD

  Study found that over half the OCD clients in the sample had experienced a traumatic event in the past, OCD was also more severe in those with more than one traumas

  This means that genetic vulnerability only provides a partial explanation for OCD
• a strength of the neural model of OCD is the supporting evidence

  Antidepressants that work purely on serotonin are effective in reducing OCD symptoms. This suggests that serotonin may be involved in OCD

  OCD symptoms from part of conditions that are known to be biological and origin, such as the degenerative brain disorder called Parkinson’s disease

  If a biological disorder produces OCD symptoms, then we may assume the biological processes underline OCD
• A limitation of the neural model is that the serotonin OCD link may not be unique to OCD

  Many people with OCD also experience clinical depression, having two disorders together is called comorbidity. This depression probably involves disruption to the action of serotonin. This causes a logical problem when it comes to serotonin as a possible basis for OCD. It could simply be that serotonin activity is disrupted for many people with OCD because they are depressed as well.