A clinical study of clozapine treatment and predictors of response in a Canadian sample

Abstract

Objective: To study the clinical response to clozapine in patients with refractory schizophrenia.

Method: Open trial of clozapine in 61 consecutively-treated patients.

Results: Following clozapine, the level of function of patients was improved relative to admission (p = 0.0001) and to the highest level in the previous year (p = 0.0001). Severity of illness was decreased (p = 0.0001). Overall, 31% of the patients were classified as responders to clozapine and the responders were all identified by 32 weeks of treatment. Poor functioning in the previous year was associated with less favourable response. At a mean interval of 26 months following discharge, 72% of the patients were continuing clozapine treatment.

Conclusions: This open trial of patients who were treated consecutively indicates a comparable degree of response to clozapine as observed in controlled clinical trials, and that level of functioning in the previous year was the best predictor of response.