February 1985

The Dexamethasone Suppression Test and Pituitary-Adrenocortical Function

Author Affiliations

From the Veterans Administration Medical Center (Dr Brown), Department of Psychiatry, Brown University (Drs Brown, Keitner, and Qualls), and Butler Hospital (Drs Keitner and Qualls), Providence, RI; and the Department of Psychiatry, University of California at Irvine (Dr Haier).

Arch Gen Psychiatry. 1985;42(2):121-123. doi:10.1001/archpsyc.1985.01790250015001

• The dexamethasone suppression test (DST) as now commonly carried out in psychiatric settings yields "abnormal" results in many conditions including the healthy state. To determine whether the DST accurately identifies patients with physiologically meaningful increases in pituitary-adrenocortical activity, we compared DST results to baseline urinary cortisol level. Thirty-four psychiatric inpatients underwent a 24-hour urine collection and then a DST using 1 or 2 mg of dexamethasone. With the common 1-mg DST, 24-hour urinary cortisol levels in nonsuppressors and suppressors did not differ. With the 2-mg DST, however, nonsuppressors had significantly higher urinary cortisol levels than suppressors, and all nonsuppressors had urinary cortisol levels above the normal range. Thus, the 1-mg DST may not identify the heuristically important subgroup of psychiatric patients who have a pathophysiologically meaningful alteration in pituitary-adrenal regulation.