Hypothalamic-pituitary-adrenocortical function in geriatric depression: diagnostic and treatment implications.

Extensive work in the field has indicated a state-dependent hyperactivity of the hypothalamic-pituitary-adrenocortical (HYPAC) functions and unresponsiveness to dexamethasone suppression in at least 50% of patients suffering from endogenous depression. In this study, elderly outpatients, 60-85 years of age, suffering from major depressive illness according to research diagnostic criteria (RDC) were studied with the dexamethasone suppression test (DST). Careful diagnostic evaluation included RDC, the Newcastle index, and clinical interviews focusing on "endogenomorphic features." The great majority (83.3%) of patients diagnosed as endogenous depressives were nonsuppressors (abnormal DST) as compared to 16.7% nonsuppressors amongst nonendogenous patients. In addition, DST tended to normalize the clinical recovery. The research and clinical implications of our findings in this population are further discussed.