The dexamethasone suppression test in outpatients with primary affective disorder and healthy control subjects

The authors report data on the overnight dexamethasone suppression test (DST) from 64 patients with primary affective disorder (41 unipolar, 17 bipolar-depressed, and 6 bipolar-hypomanic) and 53 healthy control subjects. No difference between the patients and controls was noted in baseline 8:00 a.m. serum cortisol levels or in cortisol levels obtained after the administration of 1 mg of dexamethasone. Sixteen patients and 8 controls had 4:00 p.m. postdexamethasone cortisol levels higher than 5.0 micrograms/dl. The distribution of suppressors and nonsuppressors did not differ significantly between the two groups. Patient nonsuppressors had significantly higher baseline cortisol levels than did patient suppressors (p less than .001). Clinical parameters and family history data did not distinguish patient suppressors from nonsuppressors.