Dexamethasone suppression test in major and minor depressive disorders.

The validity of the dexamethasone ofe suppression test was evaluated for the differential diagnosis of major and minor depressive disorders. Thirty-eight out-patients (14 major depressed, 14 minor depressed and 10 normal controls) were studied. The Research Diagnostic Criteria of Spitzer et al. (1978) were used to classify these patients. Six out of the 14 major depressed patients had an abnormally high plasma cortisol at 4 p.m. and at 11.00 p.m. after midnight 2 mg-dexamethasone. None of the 14 minor depressed patients and none of the 10 controls had an abnormal response to dexamethasone. Based on these results, the dexamethasone suppression test has a sensitivity of 43%, a specificity of 100% and a high predictive value.