Hypothalamo-pituitary-adrenal activity in endogenously depressed post-traumatic stress disorder patients

We studied the hypothalamo-pituitary-adrenal (HPA) system in Vietnam veterans with post-traumatic stress disorder (PTSD) who also met Research Diagnostic Criteria for endogenous depression (MDD-ED). Over half also abused alcohol, and many complained of pain - confounding factors usually associated with increased HPA activity. Nonetheless, not even one patient had elevated basal plasma cortisol concentrations or an abnormal dexamethasone suppression test (DST); the subjects' post-dexamethasone cortisol values and plasma cortisol per ng plasma dexamethasone were in the low-normal range. These results highlight the biological heterogeneity of endogenous depression and its possible influence by past psychological trauma, and they raise questions about the use of current typological criteria for research purposes.