Abstract

Case series and follow-up studies suggest that clozapine may have mood-stabilizing properties in addition to antipsychotic action in patients with schizoaffective disorder, bipolar type, and bipolar I disorder, but the generalizability of these findings is limited. This article describes a randomized, open study of clozapine add-on therapy versus treatment as usual for patients with treatment-resistant illness and a history of mania.Thirty-eight patients meeting the DSM-IV criteria for schizoaffective or bipolar disorder that was deemed treatment-resistant were randomly assigned to clozapine add-on treatment (N = 19) or treatment as usual (no clozapine) (N = 19) and followed up for 1 year. Patients received monthly ratings on the Brief Psychiatric Rating Scale, Clinical Global Impression scale, Bech-Rafaelsen Mania Scale, Hamilton Depression Rating Scale, Scale for the Assessment of Positive Symptoms, Scale for the Assessment of Negative Symptoms, Abnormal Involuntary Movement Scale, and a 40-item side effect checklist. Differences between treatment groups were assessed according to a pattern-mix random-regression model. An additional analysis compared group differences in rating scale scores against relative time in the study.Significant between-group differences were found in scores on all rating scales except the Hamilton depression scale. Total medication use over 1 year significantly decreased in the clozapine group. No significant differences between groups in somatic complaints were noted. The subjects with nonpsychotic bipolar I disorder who received clozapine showed a degree of improvement similar to that of the entire clozapine-treated group. Clozapine dose was significantly higher for the patients with schizoaffective illness than for those with bipolar disorder.The results of this study support clozapine's independent mood-stabilizing property. They demonstrate that clozapine use was associated with significant clinical improvement relative to treatment as usual.

View details for Web of Science ID 000081923300006

View details for PubMedID 10450255