Which factor is least likely to be a biological cause of depressive and bipolar disorders?

Question

Quizplus · Accepted Answer

Abnormally low levels of the stress hormone cortisol are not typically considered a primary biological cause of depressive and bipolar disorders. Other factors, such as imbalances in neurotransmitters or defects in brain regions involved in mood regulation, are generally seen as more likely to be involved in the development and maintenance of these disorders. While cortisol levels may be associated with mood and stress, research has not consistently identified cortisol as a primary cause of mood disorders.

Which Factor Is Least Likely to Be a Biological Cause