Amisulpride Augmentation Therapy for Clozapine-resistant Schizophrenic Patients

At the beginning of the treatment phase (day 1), subjects in the combination treatment group will be started with adjunctive amisulpride, with a starting dose of 200 mg per day. Amisulpride is planned to increase to 400 mg/day on day 8, 600mg/day on day 15 and 800 mg/day on day 22, according to the subjects' responses and tolerability. All of the add-on amisulpride will be provided to subjects at night. To permit dose adjustment and ensure double-blind procedure, 200mg amisulpride is packed in capsules identical to those used for the placebo.

For subjects randomly allocated to the placebo treatment group, they will be added with one capsule of placebo from Day 1. On Day 8, Day 15 and Day 22, the placebo will be increased to 2, 3 and 4 capsules, respectively. and adjunctive amisulpride, with a starting dose of 200 mg per day. Amisulpride is planned to increase to 400 mg/day on day 8, 600mg/day on day 15 and 800 mg/day on day 22, according to the subjects' responses and tolerability. To permit dose adjustment and ensure double-blind procedure, 200mg amisulpride is packed in capsules identical to those used for the placebo.