Biological Explanations of OCD (OCR A-Level Psychology): Revision Notes
4.4.2 Biological Explanations of OCD
Genetic explanation
Argues that we can inherit OCD and the specific candidate genes that cause it.
These genes are:
1. SERT gene
Affects the transport of serotonin, resulting in lower levels of serotonin being active in the brain, which is associated with OCD (as written above)
2. COMT gene
Has a variation which results in higher levels of dopamine. This variation is more common in people with OCD, suggesting that high levels of dopamine are implicated with the disorder
Evaluation for the genetic explanation:
P: There is research support for the genetic explanation from family studies
E: Research has found that if one person in a family has OCD, relatives are more likely to have it too
E: This supports the explanation by suggesting that OCD is partially inherited.
Furthermore…
P: There is further research support from twin studies
E: Twin studies have shown that 68% of identical twins share OCD
E: This strongly supports the genetic explanation by suggesting that there is a genetic basis for OCD, as identical twins share 100% of their genes
P: No twin study has found a 100% concordance rate in identical twins,
E: This means that biological factors aren't the only factor contributing to OCD. For instance, environmental factors may also play a role. Twins studies supporting the explanation may be better explained by environmental factors as twins share the same environment and are treated more similarly
E: This is a weakness as the high concordance rate from twin studies may be influenced by their environment and the genetic explanation doesn't consider this
Extra explanation - The diathesis-stress model
Use for evaluation!
P: Argues that OCD is a complex disorder and it is highly unlikely that only a few genes are solely responsible for its development.
E: For instance, the diathesis-stress model argues that genes produce a vulnerability to OCD, but environmental stressors determine whether OCD develops.
E: This suggests that biological and environmental factors combined influence whether a person develops OCD, which seems a more likely explanation