OBJECTIVE: The authors’ goal was to explore whether clozapine given as the first antipsychotic treatment favorably affects the course of schizophrenia. METHOD: Thirty-four inpatients experiencing their first episode of schizophrenia or schizoaffective disorder were treated first with clozapine and then followed for up to 4 years. In a previous study, the authors followed patients experiencing their first episode of schizophrenia or schizoaffective disorder who were given fluphenazine as the first treatment. In the current study and the previous study, response criteria required sustained remission of positive symptoms. RESULTS: Nineteen of the 34 subjects met response criteria while taking clozapine. The median time to treatment response was 11 weeks (range=2–13). Using survival analysis, the authors determined that the cumulative response rate for the 34 patients was 66.4% at the end of 13 weeks, which is comparable to the response rate to fluphenazine in the previous study. All responses to clozapine occurred by 13 weeks. Eight (42%) of the clozapine responders discontinued clozapine before 6 months, and only six (32%) remained on clozapine for all of their time in the study. CONCLUSIONS: The authors found no benefit for clozapine over conventional antipsychotics for acute treatment of the first episode of schizophrenia or schizoaffective disorder. Long-term benefits could not be studied because of the high rate of early discontinuation of clozapine treatment.