explaining OCD (biological)

• What is the genetic explanation for OCD?

  - genes r involved in vulnerability to OCD, family studies show that risk of OCD increases w genetic similarity
• What are some specific candidates genes involved in OCD?

  COMT, SERT & 5HT1D-beta -> polygenic
• What is aetiologically heterogenous?

  different combinations of genes may explain different types of OCD, multiple origins
• What is the neural explanation of OCD?

  - OCD is also associated w low levels of serotonin

  - serotonin is an inhibitory neurotransmitter that may explain low mood, anxiety & compulsive behaviour of OCD

  - structural abnormalities in the brain, e.g impaired decision making in frontal lobe, also linked to OCD
• What is a strength for the genetic explanation?

  - research support

  - Nestadt et al. found concordance rate of 68% for MZ twins & 31% for DZ twins

  - Marini & Stebnicki found someone w a family member w OCD is 4x more likely to develop it as some w/o

  - suggest there must b atleast some genetic component to OCD
• What is another strength of treatments for OCD?

  - applications to treatment

  - antidepressants increase serotonin levels r effective in reducing symptoms of OCD

  - Soomro et al. reviewed 17 studies comparing SSRIs to placebos & all showed significantly better outcomes for SSRIs

  - biological explanations provide practical applications to treatment
• What is one limitation?

  - ignores environmental factors

  - Cromer et al. found over half of patients w OCD had also had a traumatic event

  - diathesis-stress model may b more appropriate in explaining OCD