The entire night's sleep of 6 patients with manic-depressive psychosis, depressive type, was studied electroencephalographically and compared with data similarly obtained from normal subjects. The categories for the electroencephalograms were waking or daytime and sleep, the latter being subdivided into low voltage, spindles, spindles plus random, and random.
There was considerable variability among the patients in the percentage of time that each electroencephalographic type appeared during the entire night's recording. This variability became less when the waking records were excluded and only the electroencephalographic patterns that occurred in sleep were considered.
In a comparison of the mean percentage of time each electroencephalographic sleep pattern appeared in the sleep records of patients and normal controls, it was found that the patients had almost twice as much low voltage activity as the normal controls (37.5 to 19 per cent respectively) and approximately one-half as much spindles plus random activity as the normal controls (23 to 40 per cent respectively).
In a comparison of the minute by minute fluctuations from one electroencephalographic pattern or level to another for the entire night's recording of patients and normal controls, it was found that the fluctuations were more frequent for the patients.
The percent of the minutes during the night's sleep which contained two or more of the electroencephalographic sleep levels was nearly twice as great for the patients as for the normal controls (52.7 to 28.5 per cent respectively).