Explanations of OCD

Which researcher's early work observed that OCD runs in families, suggesting a genetic component?

Lewis (1936).

What does it mean that OCD is 'polygenic'?

It is not caused by one single gene, but by a combination of many (perhaps 230) different genetic variations working together.

Which researcher analyzed previous studies to conclude that OCD is polygenic and involves up to 230 genes?

Taylor (2013)

What is the key neurotransmitter in the neural explanation of OCD, where low levels are thought to disrupt mood regulation?

Serotonin.

Which part of the brain is associated with impaired decision-making in some cases of OCD, particularly hoarding disorder?

The frontal lobes (specifically the lateral parts).

Which researchers provided strong evidence for a genetic influence by reviewing twin studies and finding a 68% concordance rate for identical twins?

Nestadt et al. (2010)

What is a limitation of the genetic explanation, demonstrated by a study which found that over half of OCD clients had experienced a traumatic event?

Environmental risk factors (like trauma) also play a significant role, meaning genetics only provides a partial explanation. (Cromer et al. 2007).

What is a strength of the neural explanation, based on the effectiveness of a certain type of drug?

Antidepressants that increase serotonin activity are effective in reducing OCD symptoms, suggesting serotonin is involved.

What is a major limitation of the serotonin explanation for OCD?

The link may not be unique to OCD due to co-morbidity with depression, which also involves serotonin disruption. The serotonin issue might be related to the depression rather than the OCD itself.

What is the core issue with the evidence from biological studies, which are often correlational?

They show a link between biological abnormalities and OCD, but this correlation does not prove that the biological dysfunction causes OCD. The relationship could be reverse, or both could be influenced by a third factor.