The dexamethasone suppression test in depressed retarded adults: preliminary findings.

This study was undertaken to determine the utility of the Dexamethasone Suppression Test (DST) for diagnosing depression in institutionalized mentally retarded persons. Depressed and nondepressed institutionalized mentally retarded persons were given 1 mg dexamethasone for an overnight DST. Serum cortisol concentrations greater than 4 micrograms/dl at both 8:00 AM and 4:00 PM provided discrimination of depressed from nondepressed groups. Also, using the criteria of serum cortisol concentrations greater than 4 micrograms/dl at 8:00 AM and 4:00 PM, at 4:00 PM and 10:00 PM, or at 8:00 AM, 4:00 PM, and 10:00 PM differentiated these groups. These results suggest that the DST may be useful for detecting melancholia among institutionalized retarded persons.