Shortened REM latency PostECT is associated with rapid recurrence of depressive symptomatology

Electroconvulsive therapy (ECT) is highly effective in the treatment of major depressive disorder (MDD). The 1-year relapse rates are reported to be high and in the 30%-60% range, however. To test whether polysomnography (PS) can identify patients with a propensity for relapse we studied 20 patients, responders to a course of ECT, with PS studies. All patients met baseline diagnostic criteria for MDD, were treated with ECT following standardized protocols, had PS studies performed after the course of ECT in a medication-free state, received maintenance antidepressants postECT, and were followed periodically with phone interviews. The recurrence of depressive symptoms was determined at 3 months and 6 months after discharge. Fifty-five percent of the patients were symptomatic when evaluated 6 months after the ECT. Sleep Onset rapid eye movement (REM) periods were identified in 55% of the patients. As a group, patients who had experienced a recurrence of depressive symptoms by 6 months after discharge, had significantly shorter REM latencies after the course of ECT. A shorter REM latency after ECT identified patients who at six months demonstrated significant depressive symptomatology. Shortened REM latency after ECT in patients with MDD appears to be a correlate of vulnerability for relapse.