Research diagnostic criteria subtypes of depression. Their role as predictors of differential response to psychotherapy and drug treatment.

We studied the usefulness of the research diagnostic criteria subtypes in the prediction of response to amitriptyline and short-term interpersonal psychotherapy (IPT) in a 16-week, controlled, randomized clinical trial with 81 ambulatory depressed patients. Both patients with a situational depression and patients with an endogenous depression responded to combined treatment; those with an endogenous depression did not respond to IPT alone, whereas those with a situational depression responded to IPT or tricyclic medication alone. It may not be necessary to offer both treatments to the situationally depressed patients. However, situational and endogenous are not mutally exclusive diagnoses, and it would be of clinical interest to obtain a longer group of patients with both diagnoses for further study.