PS9: OCD: Biological Explanation

Question 1

Diathesis-Stress Model

Answer 1

• genetic vulnerability to depression
• Lewis et al. : of OCD patients; 37% had parents had OCD, 21% had siblings with OCS
• 230 different genes associated with OCD development (often associated with dopamine and serotonin functioning - regulating mood)
• candidate gene: 5HT1-D beta (involved in efficiency of synapse transmission)
• OCD also aetiologically heterogenous (it’s origin has many different causes)
• e.g. hoarding disorder caused by genetic variation

Question 2

• Eval: Little Predictive Value

Answer 2

• difficult to assess exactly which candidate genes have the greatest influence, and therefore which genes drug treatments should target
• therefore, this explanation will have little future predictive value

Question 3

• Eval: Ignores Environmental Factors

Answer 3

• Cromer et al.
• over 50% of all his OCD patients had experienced a trauma in their lives
• positive correlation between increasing number of traumas, and severity of OCD