The specificity of the dexamethasone suppression test in endogenous depressive patients.

The purpose of this study was to evaluate the specificity of the dexamethasone suppression test (DST) for endogenous depression. Between July 1983 and June 1985 we collected 51 cases of endogenous depression (including 16 bipolar disorder, depressed, and 35 major depression with melancholia), 36 cases of schizophrenia (including 14 with depression and 22 without depression), 19 cases of borderline disorder with depression, 16 cases of dysthymic disorder, and 20 normal volunteers. The sensitivity of the DST in the endogenous depression group was 62.7%, which was significantly higher than that of the schizophrenic group (36.1%), the borderline disorder with depression group (31.6%), and the control group (11.1%) (including dysthymic disorder patients and normal volunteers) (X2 = 24.48, df = 3, p less than 0.001). However, the specificity of the DST was 63.9%, 68.4%, and 88.9% when the endogenous depression group was compared with the other three groups, respectively. To differentiate endogenous depression from other mental disorders (e.g., schizophrenia, borderline disorder), such critical variables as patient history and clinical symptoms may be more valuable. Many factors that were reported to be related with DST were discussed.