OCD - explanations

• What is the genetic explanation for OCD?

  Genes inherited from parents influence OCD vulnerability
• What are candidate genes in relation to OCD?

  Genes that create vulnerability for OCD
• Which neurotransmitter does the COMT gene regulate?

  Dopamine
• What variation of the COMT gene is more common in OCD patients?

  A variation resulting in higher dopamine levels
• What does the SERT gene affect?

  Transport of serotonin
• How many different genes may be involved in OCD according to Taylor (2013)?

  Up to 230 different genes
• What does the diathesis-stress model suggest?

  Stress is needed for the gene to be expressed
• What neurotransmitter is associated with low levels in OCD?

  Serotonin
• What behavior is linked to high levels of dopamine in OCD?

  Compulsive behavior
• What effect do antidepressants that increase serotonin have on OCD symptoms?

  They reduce symptoms of OCD
• What abnormal brain structure is associated with impaired decision-making in OCD?

  Frontal lobes
• What is hypersensitivity of the basal ganglia associated with?

  Repetitive movements
• Which area of the brain is associated with processing unpleasant emotions in OCD?

  Left parahippocampal gyrus
• What did Nestadt et al (2010) find regarding identical twins and OCD?

  68% of identical twins shared OCD
• What is a counterargument to the findings of twin studies on OCD?

  They overlook shared environmental influences
• What percentage of Lewis's OCD patients had parents with OCD?

  37%
• Why is it difficult to pin down all genes involved in OCD?

  Several genes are involved, each with small effects
• What did Cromer et al (2007) find about traumatic events and OCD?

  Over half had a traumatic event in their past
• What do some antidepressants targeting serotonin suggest about OCD?

  Serotonin system is involved in OCD
• What is a limitation of the studies on neural mechanisms in OCD?

  They show correlational, not causal relationships
• What alternative explanation competes with the biological approach to OCD?

  The two-process model
• How does the two-process model explain OCD development?

  Neutral stimulus becomes associated with anxiety
• What treatment for OCD supports the two-process model?

  Exposure and response prevention
• What did Albucher et al (1998) report about OCD treatment success rates?

  60-90% of adults improved considerably
• What did Rauch et al (1994) find using PET scans in relation to OCD?

  Overactivity in the basal ganglia
• What is the co-morbidity associated with the basal ganglia?

  Tourette's syndrome