Sleep of depressed patients with hypersomnia: a 24-h polygraphic study.

Sleep of 6 depressed patients with hypersomnia was studied during their depressed phase and their remitted phase using 24-h polygraphic recording. Nine normal subjects were studied as the controls. The latency to sleep onset of the depressed patients was significantly shorter than that of the remitted patients and that of the control subjects. The total sleep time of the depressed patients was significantly longer than that of the remitted patients as well as that of the controls. This increase in sleep time of the depressed patients was mainly due to the increased sleep in day time. The intervals between sleep onset and start of each sleep stage, the relative percentage of individual sleep stages, REM latency and REM density of the depressed patients were not significantly different from those of the remitted patients.