The dexamethasone suppression test in adolescent psychiatric inpatients.

The dexamethasone suppression test (DST) was administered to 120 adolescent psychiatric patients at the time of hospitalization, and cortisol levels were measured at 4:00 p.m. and 11:30 p.m. on the day after a 1-mg oral dose of dexamethasone was given. Failure to suppress serum cortisol (i.e., cortisol level less than 5 micrograms/dl) was noted in 25 patients: 7 of 17 patients who met DSM-III criteria for major depressive disorder, 7 of 38 patients with dysthymic disorder, 7 of 47 patients with conduct disorder, and 4 of 15 schizophreniform patients. The predictive value of the DST for major depressive disorder was only 28%. Although adolescent patients with abnormal DSTs may eventually develop affective symptoms consistent with a major depressive disorder, the DST did not discriminate between major depression and other psychiatric diagnoses in these hospitalized adolescents.