Risperidone augmentation for schizophrenia partially responsive to clozapine: A double-blind, placebo-controlled trial

RationaleRisperidone augmentation of clozapine in refractory schizophrenia has theoretical but only inconsistent support from clinical trials.ObjectivesTo examine if adding risperidone to stable yet symptomatic schizophrenia outpatients on optimized clozapine monotherapy improves psychopathology.MethodsWe conducted a double-blind placebo-controlled parallel-group trial of a fixed dose of 4 mg/day risperidone added for 6 weeks in 24 outpatients with schizophrenia.ResultsSubjects who received risperidone showed a non-significant decrease in PANSS total score. The PANSS disorganized thought subscale improved significantly (β = − 3.3079, p = 0.047).ConclusionsOur trial does not support the routine addition of risperidone to clozapine in refractory schizophrenia patients. However, much larger trials are needed to conclusively settle the question of added efficacy from this combination.