Daytime sleep patterns of primary depressives: a morning nap study.

The electroencephalographic sleep patterns of 10 primary depressives were recorded during baseline nights and two morning nap sessions using a fixed time schedule. Averaged sleep measures for baseline nights replicated previous findings of altered rapid eye movement (REM) sleep patterns and sleep continuity. REM sleep during morning naps occurred only in patients with elevated REM indexes on baseline and prenap nights; it failed to appear in morning sleep of patients who exhibited contrasting REM characteristics. An analysis of hourly REM sleep distribution and averaged deviations from group means revealed significant differences between the two groups which could account for the uneven daytime REM propensity.