A psychophysiological investigation of the short-term effects of clozapine upon sleep parameters of normal young adults.

A nine consecutive night, double-blind design was used to assess the effects of a psychotropic agent (clozapine) upon sleep parameters as well as measures of mood and performance in a group of seven normal, young adults. Placebo was administered to a control group of seven subjects. EEGs and EOGs were monitored throughout the night in a laboratory environment and were scored according to standardized criteria. The administration of 25 mg clozapine/night for three consecutive nights significantly reduced stage 4 sleep on the second and third nights. Whereas stage REM sleep was not affected, a variety of REM indices were significantly increased on the third night of clozapine administration and/or on the first night of clozapine withdrawal. The number of body movements and the number of body movements/minute of sleep were significantly reduced on the three nights of clozapine administration. Numerous psychophysiological side effects were reported. These results indicate that clozapine may be a useful medication in the treatment of sleep disorders. However, the incidence of adverse side effects of represents a major limitation in the use of clozapine as an hypnotic agent at the dose-rate employed.