Genetic explanations of OCD

what is the genetic explanation of OCD

1. Hereditary- runs in families, pass on genetic vulnerability from one generation to next, if one twin suffers the other would too

2. Candidate genes- specific genes which influence vulnerability to OCD

AO1 research support for hereditary genetic explanation

- Family studies- NESTADT et al. (2000)- 11.7% probability of OCD when have a 1st degree relative with the disorder c.w. 2.7% in a control group

- Twin studies- MIGUEL et al. (2005)- concordance rate between 53-87% of identical twins

AO1 support for candidate genes genetic explanation

TURKEL et al. (2013)- COMT gene- regulates activity of dopamine, one variation causes higher levels of dopamine, more common in OCD suffers than normal controls

strength of the genetic explanations of OCD- empirical support from twin and family studies

- Nestadt et al. (2010)- 68% concordance rate for OCD in MZ twins c.w 31% in DZ twins- strong genetic influence

- Lewis (1936)- 37% of OCD patients had parents with disorder, 21% had siblings with disorder

- findings support genetic link, enhancing validity of explanation

strength of genetic explanations of OCD- identification of specific candidate genes

- strengthened by identifying specific genes e.g. COMT and SERT

- COMT- affects dopamine, variant linked to higher dopamine = compulsions

- SERT- influences seratonin transport, assoiciated with lower seratonin = mood regulation affected

- associations give insight to biological basis of OCD- potential target for treatments

- OCD is polygenic, cannot treat disorder solely on genetics

- complexity suggests genetic research valuanle, cannot provide a complete understanding

weakness of genetic explanations of OCD- oversimplification and reductionism

- simplifies OCD to genetic factors minimises role of environmental factors, e.g. trauma

- Cromer et al. - over half OCD patients had experienced trauma, highlights importance of non-genetic factors

- focus on genetics misses crucial aspects, limiting effectiveness of treatments

- other factors have role to play in developing OCD , e.g. learning

weakness of genetic explanations of OCD- incomplete concordance rates

- twin studies show genetic component but concordance rates not 100%

- Nestadt et al. - 68% concordance rate for identical twins- ither factors contribute ot OCD development

- genetics alone cannot explan disorder

- twin studies involve shared environments- difficult to separate genetic influences from environmental ones

- suggests comprehensive understanding of OCD must consider interaction between genetic and environmental ones