The dexamethasone suppression test predictive of the therapeutic response to specific antidepressants

Abstract

SummaryThe value of the Dexamethasone Suppression Test (DST) in predicting the therapeutic response to a specific antidepressant is a very controversial topic, probably due to methodological issues. The aim of this study was to evaluate the power of the DST in predicting the response of primary and secondary depressives, diagnosed according to Feighner criteria, to either clomipramine or maprotiline. Patients were screened using standardized psychiatric interview, Current and Past Psychopathology Scales, the Hamilton Rating Scale for Depression (HRSD), and the Beck Depression Inventory (BDI); the Michigan Discriminant Index was determined providing an endogeneity score. A 1 mg DST was performed. Treatment was assigned double blind and at random, according to a fixed schedule with administration of up to 225 mg of either drug for three weeks. After this period patients were again evaluated with the Hamilton Rating Scale for Depression and Beck Depression Inventory, and a DST was again performed.Treatment reponse was defined in terms of reduction of HRSD and BDI scores. Serum levels of antidepressants were documented in a number of patients.HRSD score reduction did not yield any significant results.Insofar as BDI score reduction was concerned, nonsuppression on the DST (i.e. a post-dexamethasone cortisol value greater than or equal to 50 μg/l) predicted a better, or anyway a quicker, response to maprotiline; the DST results did not predict response in patients treated with clomipramine.Despite some methodological pitfalls (a relatively small group of patients, insufficiently documented serum antidepressant levels) these results seem to warrant further investigation in this field.