The dexamethasone suppression test: its relationship to diagnoses, severity of depression and response to treatment.

1. The dexamethasone suppression test (DST) was applied to 40 depressed patients, 40 healthy volunteers and 40 patients with other psychiatric disorders. 2. The post-dexamethasone cortisol level, adopted as the non-suppression criterion and established locally, was 3.0 micrograms/dl. 3. The DST sensitivity in depression was 45%, with a specificity of 95% and a positive predictive value of 90%. 4. There was a significant correlation (r = 0.38, p less than 0.05) between HDRS scores of depressed patients and their post-dexamethasone cortisol levels. 5. A prospective study of the depressed group, which was assessed with three depression rating scales, showed differences between non-suppressors and suppressors regarding to the symptoms severity and response to the treatment. It suggests that an abnormal DST result could have a prognostic value to antidepressant drugs and ECT. 6. The DST specificity in depression was also calculated from its performance in the group with other psychiatric disorders, and their diagnoses as well as the abnormal DST results were critically discussed.