Amisulpride: is there a treatment for negative symptoms in schizophrenia patients?

In this article we report on a meta-analysis of the published studies of amisulpride conducted in order to demonstrate efficacy on primary negative symptoms in schizophrenia. Four placebo-controlled studies were conducted in patients with predominantly negative symptoms. In all studies a significant improvement was observed on the Scale for the Assessment of Negative Symptoms (SANS) in the amisulpride groups (50-300 mg daily) as compared to placebo. The improvement on the SANS was not accompanied by a simultaneous improvement on the Scale for the Assessment of Positive Symptoms (SAPS) or a decrease in extrapyramidal symptoms (EPS) in three of the four studies, indicating a genuine effect on primary negative symptoms. The overall analysis shows that the improvement on the SANS was accompanied by a small simultaneous improvement on the SAPS. Moreover, in the studies where depressive symptoms were measured, a significant improvement was also shown in favor of amisulpride. However, as the SAPS and the Montgomery Asberg Depression Rating Scale (MADRS) baseline scores were rather low, the improvement on both scales in favor of amisulpride is probably not responsible for the improvement on the SANS. A positive correlation was found between the severity on the mean SANS score at baseline and mean improvement at endpoint, and a surprisingly high success rate was observed in the placebo groups, indicating either that primary negative symptoms are not as persistent as had previously been thought, or that the concept of primary negative symptoms should be reconsidered. Probably amisulpride is efficacious on these nonenduring primary negative symptoms.