The Dexamethasone Suppression Test Findings in Psychiatric Inpatients

Abstract

83 subjects(20 normal controls, 15 neurotics, 19 major depressives and 29 paranoid schizophrenics) underwent the dexamethasone suppression test(OST) to test the applicability of the test for the diagnosis of major depression. Pre- and post-dexamethasone serum cortisol concentrations were determined in duplicate by radioimmunoassay at 8:00 a.m., 4:00 p.m. and 11:30 p.m. Significantly decreased suppressibility of serum cortisol levels were found in the major depressives at 8:00 a. m. and 4:00 p.m. in the OST and the cortisol suppression index(CSI), compared with those in the normal controls. No significant differences were found in the other comparisons. The nonsuppression rate in the major depressives was 47%. And due to the significant nonsuppression rates(14%-22%) in the other groups, the specificity of the nonsuppression in the OST needs to be further clarified before its significance is established. In the meantime, it is recommended that multiple chronological OSTs be performed during the clinical course and other intervening variables should be considered for meaningful interpretation.