Dexamethasone suppression test and REM sleep in patients with major depressive disorder.

Dexamethasone suppression Test (DST) and sleep electroencephalogram (EEG) recordings were carried out during three consecutive nights in 39 depressed patients who met Research Diagnostic Criteria (RDC) for major depressive disorder and in nine normal controls. Cortisol response to DST was abnormal in 26 patients and normal in all controls. REM latency and REM density were compared in patients with abnormal DST (n = 26) to values obtained in patients with normal DST (n = 13) and in normal controls (n = 9). Rapid Eye Movement (REM) latencies were significantly lower in depressed patients showing cortisol non-suppression after dexamethasone than in patients with a normal DST or in controls. REM densities were significantly higher in depressed patients than in normal controls (P less than 0.025), but there was no significant difference between DST suppressors and non-suppressors. The DST provided high specificity (100%) and a sensitivity of 67%, while REM latency showed a lower specificity (78%), but a higher sensitivity (85%).