Biological approach to explaining OCD

Genetic explanations: family studies

• Lewis: 37% of OCD patients had parents with OCD.

• 21% with siblings with OCD.

• however diathesis model suggests may not develop if dont experience trigger.

candidate genes

• certain genes that increase risk of development.

• SERT + COMT: regulate dopamine and serotonin in synapses.

• low serotonin: anxiety/OCS symptoms.

Polygenic

• OCD caused by a combination of genes (up to 230 genes)

aetiologically heterogeneous

• group of genes may cause OCD in one person but a different group in someone else

2) neural explanations: serotonin

• serotonin: helps regulate mood.

• low levels of serotonin leads to anxiety and intrusive thoughts.

impaired decision making

• abnormal functioning on lateral sides of frontal lobe.

• may not work properly leading to people with OCD struggling to make decisions.

• parahippocampal gyrus: links to unpleasant thinking

strength - research to support

• research to support in family studies.

• Nestadt et al reviewed twin studies that 68% of MZ twins had OCD compared to 31% of DZ twins.

• people with a family member who has OCD are 4x more likely to develop.

• supports biological approach showing increase in vulnerability.

limitation - environmental risk factors

• a limitation of the genetic explanation is it ignores environmental influences.

• Cromer et al found that over half of OCD patients in sample had traumatic pasts.

• shows environmental stressors play a significant role in worsening OCD

• suggests not purely genetic

limitation - animal studies

• often relies on animal studies may not fully apply to humans.

• Ahmari found certain genes are linked to repetitive behaviours in mice.

• humans are more complex and experience psychological processes.

• difficult to generalise due to complexity of human symptoms