Role of REM sleep and dream variables in the prediction of remission from depression.

To test the hypothesis that REM sleep and/or dreams contribute to overnight mood regulation, 61 subjects were tested on the Beck Depression Inventory (BDI), and for 3 nights of monitored sleep on two occasions, once close to, and 1 year after, a marital separation. Forty-nine percent of the variance in the follow-up BDI could be accounted for by the initial BDI score, and three sleep and dream variables associated with the mood regulatory hypothesis: eye movement density in the first REM, strength of the affect in the first dream and total number of negative dreams recalled from REM awakenings. Among the 39 who met BDI depression criteria initially, 71.8% could be classified correctly as remitted or not remitted at follow-up by discriminant function analysis based on the presence of negative dreams the first vs. second half of the night. Subjects reporting more negative dreams at the beginning and fewer at the night's end were more likely to be in remission 1 year later than were those with fewer negative dreams at the beginning and more at the end of the night. Early negative dreams may reflect a within-sleep mood regulation process taking place, while those that occur later may indicate a failure in the completion of this process.