Electroencephalographic sleep abnormalities in schizophrenia. Relationship to positive/negative symptoms and prior neuroleptic treatment.

Polysomnographic abnormalities in schizophrenia are not well characterized and their associations with schizophrenic symptomatology have not been adequately assessed. To address these issues, we recorded electroencephalographic sleep in 20 drug-naive schizophrenics, 20 drug-free but previously medicated schizophrenics, and 15 normal controls. Drug-naive and previously medicated patients had significantly greater impairment of sleep continuity and shorter rapid eye movement latency when compared with controls. In the previously medicated group, findings were significantly influenced by duration of drug-free status. Rapid eye movement latency was inversely correlated with the severity of negative symptoms (r = -.52) but was unrelated to depressive symptoms. Slow-wave sleep did not differ between schizophrenic patients and normal controls and was unrelated to any clinical parameter. Mechanisms underlying the observed associations between rapid eye movement sleep abnormalities and negative symptoms in the acute phase of schizophrenic illness need to be explored.