Chronobiological comparison of sleep-wake rhythm between chronic schizophrenia and normal control.

Few studies on schizophrenia with respect to the circadian alteration of the sleep-wake rhythm have been reported. We made a comparative study of the sleep-wake rhythm between chronic inpatient schizophrenics with a relatively bed-prone daily life and normal subjects under the conditions of absolute bed-rest to elucidate the chronobiological features of schizophrenia. The sleep-wake rhythm of the schizophrenics differed from that of the normals in two points: A significant difference was observed in the decrease of Stage 4 during their nocturnal sleep compared with the normal subjects, becoming conspicuous with the increasing lapse of time during sleep. The distribution and amount of their REM sleep in the morning were markedly low and the latency of their REM sleep was also prolonged. These facts suggested that the smooth slide of the sleep-wake rhythm was somewhat disturbed in the schizophrenics and that they were, therefore, in a state of hyperarousal despite their bed-prone life.