The role of hypothalamic pituitary-adrenal axis dysfunction in the etiology of depressive disorders.

There is a growing body of evidence regarding the abnormalities of cortisol and its regulatory system in both unipolar and bipolar depression. Cortisol may contribute to some of the symptoms experienced by depressed persons. There is a complex, bidirectional relationship between serotonergic and stress systems and disruption of one may create a cascade of events that will lead to ill health. Novel therapeutic approaches that modulate cortisol are now being evaluated experimentally in order to increase treatment options for depression and improve patient outcome.