Serial dexamethasone suppression test in psychiatric inpatients.

A sample of 100 consecutively admitted cases were recruited to test the hypothesis that an abnormal dexamethasone suppression test (AbDST) is associated with decreasing clinical severity during the course of hospitalization in various diagnostic categories. Serial DSTs and psychopathological ratings were done at the end of the first and the third week postadmission, and 1 week before discharge. DST was also done at 1-year follow-up after discharge. The results of this study strongly suggest that a dual mechanism is responsible for the prevalence of AbDST. One is related to the global psychopathology of a nonspecific quantitative mechanism in various diagnostic categories. The other is a specific qualitative mechanism relating to the depressive state, as reflected in the higher prevalence of AbDST and more consistent AbDST results across different study time points in melancholia, and also in higher AbDST rates in disorders with higher depressive scores.