Genetic Explanation for OCD

• What is the focus of the biological explanations for OCD?

  Genetics
• What is the purpose of twin studies in investigating OCD?

  • Recap knowledge of twin studies
  • Practice drawing conclusions
  • Investigate genetic basis of OCD
• What percentage of OCD patients had parents with OCD according to Lewis (1936)?


  37%
• What does the Diathesis Stress model suggest about OCD?

  Some genes increase likelihood, but stress triggers it
• What are candidate genes in relation to OCD?

  Genes that create vulnerability for OCD
• What role does the COMT gene play in OCD?

  Regulates dopamine production implicated in OCD
• What specific form of the COMT gene is found more commonly in OCD patients?

  Lower activity form
• What does the SERT gene affect in relation to OCD?

  Transport of serotonin, creating lower levels
• What did Ozaki et al (2003) find regarding the SERT gene?

  Mutation found in two families with OCD
• What does it mean that OCD is polygenic?

  Caused by multiple genetic variations
• How many different genes did Taylor (2013) find may be involved in OCD?

  Up to 230
• What neurotransmitters are associated with OCD according to genetic studies?

  Dopamine and serotonin
• What does aetiologically heterogenous mean in the context of OCD?

  Origins of OCD vary from person to person
• What are the implications of different types of OCD?

  • Result from particular genetic variations
  • Examples include hoarding disorder and religious obsessions
• What did Nestadt et al (2010) find in their review of twin studies?

  68% of MZ twins shared OCD
• What did Marini & Stebnicki (2012) conclude about family history and OCD risk?

  Family member increases risk by 4 times
• What did Kiara Cromer et al (2007) find about traumatic events and OCD?

  Over half of OCD clients experienced trauma
• What did Ahmari (2016) find in animal studies related to OCD?

  Particular genes linked to repetitive behaviors
• What should be evaluated about the studies on genetic research for OCD?

  • Determine if each study is a strength or weakness
  • Explain the reasons for their evaluations
• What does OCD stand for?

  Obsessive-Compulsive Disorder
• How do environmental factors relate to the development of OCD?

  They can trigger the condition in predisposed individuals
• Why is it important to understand the polygenic nature of OCD?

  It helps in understanding the complexity of the disorder