Electroencephalographic sleep in schizophrenia: a critical review.

Several polysomnographic abnormalities seem to occur consistently in schizophrenic patients: impaired sleep continuity and reduced total sleep, reduced amounts of slow wave sleep, and reduced rapid eye movement (REM) sleep latency and defective REM rebound following REM deprivation. None of these findings is specific for schizophrenia, and only a subgroup of schizophrenic patients seem to have these abnormalities. It appears that reduced slow wave sleep may be related to a neurodevelopmental disorder related to the defect state in schizophrenia. The pathophysiological significance of the defective REM rebound and the REM sleep abnormalities in schizophrenia remain uncertain. Carefully designed studies are needed to further characterize the sleep disturbance in schizophrenia and to study them in relation to other, known pathophysiological changes in this disorder.