Abstract

Although the major classes of antidepressant drugs have been available for over 30 years, clinicians are still unable to predict accurately the response of their depressed patients to medication. This article reviews both clinical and biologic predictors of treatment response and makes recommendations for future studies. The tricyclic antidepressants remain the drugs of choice in major depressive disorders. Lithium has a place in bipolar depressions. Monoamine oxidase inhibitors have a role in depressions accompanied by marked anxiety and/or panic symptoms, in patients who have previously responded to them, and as a second-choice treatment in those depressed patients who have not responded to tricyclic antidepressants. Electroconvulsive therapy or additional antipsychotic drugs are frequently necessary in very severe and delusional depressions. Biologic predictors of response, despite some interesting leads that may in the long term be of considerable importance, are not yet sufficiently established to be of routine clinical usefulness, although either dexamethasone nonsuppression or a shortened rapid eye movement latency may identify depressed patients who require biologic treatment.