The clinical diagnostic value of dexamethasone suppression test in depressive illness

Dexamethasone suppression test (DST) was done for Chinese melancholics. The overall sensitivity of DST is 41.0%, and its specificity is 85%. The prevalence of abnormal DST is higher in inpatient melancholics (66.7%) than in outpatient melancholics (7.1%). Three schizophrenic patients who had abnormal DST were found to have severe degree of depression and impaired social function. The clinical diagnostic value of DST for severely impaired inpatient was tested. 35.7% of primary depressives (28 cases) had abnormal DST. 50% of secondary depressives (26 cases) had abnormal DST. 11 cases (50%) of 22 initially admitted, undiagnosed cases were found to have abnormal DST. 5 (45.5%) of these 11 cases were of primary depressives. 6 (54.5%) of these were of secondary depressives. DST was found to be of limited value in differential diagnosis for inpatient undiagnosed cases. Yet, DST could be a powerful research tool in psychopathology.