Electroencephalographic sleep in recently remitted, elderly depressed patients in double-blind placebo-maintenance therapy.

The aim of this double-blind placebo-controlled study was to assess the effects of clinical state on electroencephalographic (EEG) sleep measures in elderly patients with recurrent major depression. We hypothesized that rapid-eye movement (REM) latency and delta sleep ratio would remain stable between actively depressed and remitted states (i.e., show state independence), and measures of sleep continuity would improve with remission (i.e., show state dependence). Fifteen elderly outpatients (mean age 65.3 years) had sleep evaluations while ill and after remission, an average of 38 weeks later. All patients were in a double-blind placebo-maintenance condition at the time of follow-up studies. The major findings were: 1) no significant change in either REM latency or delta sleep ratio; 2) reduction in early morning awakening; and 3) improvement in subjective sleep quality despite the stability of most polysomnographic measures. We conclude that REM latency and delta sleep ratio are state-independent in patients with late-life depression, and that early morning awakening and sleep quality improve with remission of symptoms. These findings suggest that EEG sleep changes may have significance for understanding the longitudinal course of depression in late life.