Electroencephalographic sleep profiles in recurrent depression. A longitudinal investigation.

The electroencephalographic sleep profile of a group of recurrent depressives who had been depressed for less than four weeks was compared with their sleep profile in a prior episode of depression. The findings in these 19 cases indicate that early in the episode, rapid eye movement (REM) sleep findings are more abnormal, including shortened REM latency, REM sleep percent, and REM activity. Other sleep variables, such as sleep continuity measures and decreased delta-wave sleep, are abnormal in a similar fashion in both episodes. The results are not explainable on the basis of clinical severity or number of episodes and call for increased attention to the potential relationships between the psychobiological pattern and duration and course of the depressive episode.