Electroencephalographic sleep in young, never-medicated schizophrenics. A comparison with delusional and nondelusional depressives and with healthy controls.

Electroencephalographic (EEG) sleep characteristics of young, never-medicated, nonschizoaffective schizophrenics were compared with the EEG sleep of patients with major depressive disorders (delusional and nondelusional) and with that of healthy controls. Schizophrenics had decreased sleep continuity comparable to delusional depressives. Slow-wave sleep percent was similar to that seen in healthy controls, as was the intranight temporal distribution of EEG delta activity. However, schizophrenics showed diminished delta counts per minute of non-rapid eye movement (NREM) sleep and a decreased total delta wave count. In contrast, depressives showed diminished slow-wave sleep percent compared with controls, greatly decreased delta activity (more so than did the schizophrenics), and an altered temporal distribution of delta activity, as evidenced by a shift of delta activity from the first to the second NREM period. Minutes of slow-wave sleep in the schizophrenics was inversely correlated with the severity of negative symptoms independent of the effects of age and the presence of depression. The schizophrenics showed normal REM latency and first REM period duration, in contrast to the depressives. These findings, reviewed in the historical context of sleep physiologic studies of schizophrenia over the past 30 years, suggest that young, never-medicated schizophrenics do not show the characteristic constellation of abnormalities in the first NREM-REM cycle seen in patients with major depression. However, decreased slow-wave sleep should be investigated as a possible marker for negative symptoms in schizophrenia.