Biological explanation of OCD

• What role do genes play in OCD according to the biological approach?

  Genes are involved in individual vulnerability to OCD.
• What did Lewis (1936) find regarding the family history of his OCD patients?

  37% of his OCD patients had parents with OCD and 21% had siblings with OCD.
• What does the observation by Lewis (1936) suggest about OCD?

  OCD runs in families, indicating genetic vulnerability rather than certainty of OCD.
• What is the diathesis-stress model in relation to OCD?

  Certain genes increase the likelihood of developing OCD, but environmental stress is needed to trigger it.
• What are candidate genes?

  Candidate genes are those identified by researchers that create vulnerability for OCD.
• How do some candidate genes relate to OCD?

  Some candidate genes are involved in regulating the development of the serotonin system.
• What does it mean that OCD is polygenic?

  OCD is caused by a combination of genetic variations that increase vulnerability.
• What did Taylor (2013) find regarding the number of genes involved in OCD?

  Taylor found evidence that up to 230 different genes may be involved in OCD.
• Which neurotransmitters are associated with genes studied in relation to OCD?

  Dopamine and serotonin are the neurotransmitters involved in regulating mood related to OCD.
• What does it mean that OCD is aetiologically heterogeneous?

  It means the origins of OCD differ from person to person.
• What evidence suggests that different types of OCD may arise from genetic variations?

  There is evidence indicating that different genetic variations may lead to different types of OCD.