Genetic explanations for OCD

• Genes are involved in individual vulnerability to OCD
• What did the study by Lewis suggest?

  OCD runs in families
• What percentage of OCD patients studied by Lewis had parents with OCD?

  37%
• What percentage of OCD patients studied by Lewis had siblings with OCD?

  21%
• Who studied OCD patients and suggested OCD runs in families?

  Lewis
• What did the findings from Lewis's study suggest?

  OCD runs in families
• According to what model do certain genes leave people more likely to develop a mental disorder (i.e OCD)?

  Diathesis-stress model
• What is necessary to trigger OCD?

  Some environmental stress
• What genes have been identified by researchers that create vulnerability for OCD?

  Candidate genes
• Like many conditions, what does OCD seem to be?

  Polygenic
• What does it mean if OCD is polygenic?

  It isn't caused by one gene, but a combination of genetic variations
• How many genes did Taylor find may be involved in OCD?

  230
• What genes have been studied in relation to OCD?

  Dopamine and serotonin
• What does it mean if OCD is aetiologically heterogeneous?

  The origins of OCD vary from one person to another
• What term is used to describe that the origins of OCD vary from one person to another?

  Aetiologically heterogenous
• There is evidence to suggest different types of OCD may be the result of particular genetic variations
• Strength: Genetic explanation for OCD

  What? Research support

  Who? Twin studies; Nestadt - 68% of identical twins share OCD

  Family studies - a person w/ a family member w/ OCD is four times as likely to develop it as someone without

  Why? Suggests some genetic influence on OCD
• Limitation: Genetic explanation for OCD

  What? Environmental risk factors

  Who? Cromer - over half of OCD clients in their sample had experienced a traumatic event in their past

  Why? Genetic vulnerability only provides partial explanation