Clinical update on amisulpride in deficit schizophrenia

Amisulpride is an atypical antipsychotic drug. Low doses increase dopaminergic transmission via presynaptic blockade and are effective in patients with predominantly negative (deficit) symptoms of schizophrenia. In three double-blind studies, two short-term and one medium/long-term, comparing amisulpride with placebo, 272 patients with schizophrenia were carefully selected for a predominance of negative symptoms (low severity of positive symptoms, depression and extrapyramidal side effects). Fixed daily doses of amisulpride (100 and 300 mg) were used in a 6-week dose-range finding study (104 patients). Daily doses of between 50 and 100 mg amisulpride were used in a second 6-week study (27 patients), and in a third study, 100 mg amisulpride was administered for 6 months (141 patients) with an extension of up to 1 year. Mean total scores for the Scale for the Assessment of Negative Symptoms (SANS) at baseline in the different treatment groups varied from 98 to 74, and improved significantly in the amisulpride groups (mean change from 24 to 40 points) compared with the placebo groups. Positive symptoms measured by the Scale for the Assessment of Positive Symptoms (SAPS) were low at baseline, and the change at the end of the studies was minimal. Extrapyramidal side effects were of low severity in these studies and parkinsonism scores for amisulpride were not different from placebo. Overall, these findings indicate that the improvement in negative symptoms was not linked to a concomitant improvement in positive symptoms, parkinsonism or depressive symptoms as would be expected in the case of secondary negative symptoms. The results of these studies thus confirm the efficacy of amisulpride in schizophrenic patients with primary negative or deficit symptoms at a dose of 100 mg/day.