Amisulpride augmentation of clozapine: an open non-randomized study in patients with schizophrenia partially responsive to clozapine

Objective: Treatment options are very limited for individuals with schizophrenia resistant to clozapine. We tested the hypothesis that amisulpride augmentation would lead to an improvement in these patients. Method: This was an open non-randomized study. Thirty-three patients with sub-optimal response to clozapine were commenced on amisulpride in addition to clozapine. Clinical status was evaluated at baseline, 3 and 6 months using the Positive And Negative Syndrome Scale (PANSS), Scale for the Assessment of Negative Symptoms (SANS), Global Assessment Scale (GAS), Calgary Depression Scale, Calgary Anxiety Scale and various side effect rating scales. Results: Twenty-eight subjects completed 6 months treatment on clozapine and amisulpride. There was a statistically significant improvement in the mean scores for PANSS, SANS and GAS at follow-up and no significant changes in side effect ratings. Conclusion: Co-administration of amisulpride, in a group of patients partially or non-responsive to clozapine, may lead to a substantial improvement in positive and negative symptoms, without worsening the side effect burden.