The electroencephalographic sleep pattern in schizophrenic patients treated with clozapine or classical antipsychotic drugs.

The effects of antipsychotic agents on sleep were tested by examining the nocturnal electroencephalographic recordings of 14 drug-naïve schizophrenic patients and comparing these with recordings from 12 patients treated with clozapine and 10 treated with classical neuroleptics (haloperidol: n = 7; flupentixol: n = 3). In both of the treated groups, sleep continuity measures and rapid eye movement (REM) density were significantly higher than in the drug-naïve group. Clozapine-treated patients showed significantly more stage two sleep, more stable non-REM sleep (stages two, three and four) and less stage one than patients treated with haloperidol or flupentixol. Clozapine had no effect on the amount of REM sleep. Although mean REM latency was almost twice as long in the clozapine compared with the other two groups, this difference was not statistically significant. The present study suggests considerable differences between the influence of typical and atypical antipsychotic agents on sleep. However, the results of this cross-sectional study should be confirmed using a longitudinal intraindividual approach.