Effects of clozapine on sleep in bipolar and schizoaffective disorders

OBJECTIVE: Sleep disturbances are strongly associated with mood disorders, although the majority of data have been obtained in patients with major depressive disorder. Studies reporting results in bipolar disorder are few, and results have not been consistent. Clozapine is a prototype of atypical antipsychotics, which is effective in improving symptoms of manic episodes in patients with bipolar disorder, or schizoaffective disorder, bipolar type and has been shown to influence sleep in other psychiatric disorders. The present study evaluated the sleep effects of clozapine in bipolar and schizoaffective disorders. METHODS: Participants were 11 women and 4 men (range:28-53 years of age, mean 40.9+/-8.6 years), all with a history of mania by DSM-IV criteria for either bipolar I disorder or schizoaffective disorder, bipolar type. They participated in a sleep study at baseline and again after 6 months initiation of clozapine add-on therapy. RESULTS: Sleep latency was longer on clozapine and the number of awakenings were increased, whereas time in bed (TIB) and total sleep period (TSP) were increased (range: F=6.2-17.9; df=l,12; p<0.05). Although none of the individual sleep stage showed significant treatment changes, both Stage 2 and slow-wave sleep were increased and Stage 2 decreased on clozapine. Subjective sleep measures improved on clozapine with a small but significant improvement in how rested patients felt upon awakening (t=-2.1; df=26; p<0.05). CONCLUSION: Clozapine prolonged sleep latency, improved restedness, and increased total sleep time. Although lack of a control group limits interpretation of these results, they are in general agreement with studies in other psychiatric populations, and support the view that clozapine is primarily a NREM sleep enhancer. The improvement in restedness may be of positive clinical consequence.