Dexamethasone Suppression Test by Urinary Free Cortisol in Depression Measuring Spot Shin-ichiro Tomitaka, Kaoru Sakamoto, Atuko Tamura, Ram Kojima, and Hiroko Fujita Key Words: Depression, urinary free cortisol, dexamethasone BIOL PSYCHIATRY 1996;39:220--222 Introduction Among various neuroendocrinoiogical investigation in affective disorders, the dexamethasone suppression test (DST) has drawn much attention as a specific laboratory test for endogenous depression (Carroll et al 1981; Carroll 1982). However, two problems with ~the DST have arisen according to subsequent studies. First, several reports have raised questions about the sensitivity and specificity of DST for depression (Arana et al 1985; Coppen et al 1987). Second, to follow the procedure of the standard DST (Carroll et al 1981), subjects must be hospitalized and undergo several venipunctures. To resolve these problems, several researchers have attempted to improve the DST (Hanada et al 1985; Zis et al 1987; Maes et al 1991). Endocrinologists have recently reported that spot determina- tions of urinary free cortisol (UFC) are more sensitive and specific than those of plasma cortisol in diagnosing Cushing's syndrome (Allin et al 1984; Conteras et al 1986; Fujita et al 1991). Because urine specimens contain only free cortisol and reflect the bioactive component (Slauntwhite 1962), UFC may be better for assessing the hypothalamic-pituitary-adrenocortical (HPA) axis than plasma cortisol. In addition, this method enables patients to collect samples at home without undergoing invasive venipuncture. In the present study, we determined the correlation between From the Department of Psychiatry, Tokyo Women's Medical College (ST, KS, AT); Institute for Molecularand CellularRegulation,Gunma University(IK); and Fourth Department of Internal Medicine,University of Tokyo Schoolof Medicine, Tokyo, Japan (HF). Address reprint requests to Shin-ichiroTomitaka, M.D., Department of Cortical Function Disorder, National institute of Neuroscience, National Center of Neurologyand Psychiatry (NCNP), 4-1-10gawahigashi, Kodaira, Tokyo 187, Japan. ReceivedDecember 30, 1994; revised July 6, 1995. UFC levels and total serum cortisol levels and assessed the usefulness of the spot UFC determinations in major depression. Methods The subjects consisted of 14 patients admitted consecutively to the Psychiatry Ward of the Tokyo Women's Medical College from January 1992 to December 1992, and they (six men and eight women, aged 26-58 years, mean 35) met research diag- nostic criteria (Spitzer et al 1978) for major depressive disorder. No patient had any of the exclusion criteria proposed by Carroll (1982) and all gave informed consent to participate in this study. The severity of the clinical psychopathology was assessed by the Hamilton Rating Scale (HRSD) (Hamilton 1960). The HRSD score (mean _+ SD) in patients with major depression was 20.5 ± 3.7. The study protocol did not determine or influence treatment. Except for two patients, the other patients were treated with psychotropics known not to interfere with the DST (Carroll et al 1981), low-dose neuroleptics, benzodiazepines (no more than 20 mg of diazepam equivalents per day), lithium, and, most com- monly, tricyclic antidepressants. In the urinary cortisol DST procedure, 1 mg dexamethasone was given orally at 11:00 PM on day 1. Urine samples were collected at 8:00 AM and 11:00 PM on day 1, and at 8:00 AM and 4:00 PM, and 11:00 PM on day 2 (minor deviations of up to -+ 2 hours from these times were permitted). Urine samples were collected after urine had been voided 1-2 h before scheduled time. Plasma cortisol was obtained immediately after the urinary sample was collected. DST nonsuppression was defined as a plasma cortisol level greater than 5 ixg/dL at 4:00 PM or 11:00 PM on day 2. The DST was done during the week after admission. Four depressed patients were DST nonsuppressors and the remaining 10 patients were DST suppressors. © 1996 Societyof BiologicalPsychiatry 0006-3223/96/$15.00 SSDI 0006-3223(95)00375-Q