Aripiprazole augmentation of clozapine in treatment-resistant schizophrenia: a clinical observation.

Background: Therapeutic options for patients with treatment-resistant schizophrenia are limited, and combination treatment with atypical antipsychotic drugs is an often used strategy. We tested the hypothesis that the combination of aripiprazole and clozapine would lead to an improvement in this patient group.

Methods: Eleven patients with treatment-resistant schizophrenia participated in this clinical trial and received a combination of aripiprazole and clozapine. Patients had to have remained on a stable dose of clozapine for at least 6 months in order to ensure a reasonable opportunity to respond to clozapine monotherapy. Clinical status was evaluated at baseline and at 3 months' follow-up using the Brief Psychiatric Rating Scale (BPRS).

Results: All patients completed 3 months' combination treatment. There was a significant reduction in the mean BPRS score in seven patients (63.6%) over the 3 months of combination treatment. Augmentation with aripiprazole in clozapine-treated patients did not result in a corresponding increase in adverse effects. Use of the combination allowed a significant reduction in the daily dose of clozapine.

Conclusions: Combined application of clozapine and aripiprazole is in accordance with a neurobiological rationale and appears to be safe and well tolerated without increased risk of adverse effects.