Ziprasidone and amisulpride effectively treat negative symptoms of schizophrenia: results of a 12-week, double-blind study.

We compared the efficacy of ziprasidone and amisulpride in the treatment of negative symptoms and overall psychopathology in subjects who had chronic schizophrenia with predominantly negative symptoms. This multicentre, 12-week, double-blind study randomly assigned subjects with predominantly negative-symptom schizophrenia [i.e. Positive and Negative Syndrome Scale (PANSS) Negative Subscale score >or=6 points greater than Positive Subscale score] to ziprasidone (40-80 mg b.i.d.; n=60) or amisulpride (50-100 mg b.i.d.; n=63). The primary efficacy variable was the change from baseline in PANSS Negative Subscale score. Secondary efficacy variables included change in scores for PANSS Total, Global Assessment of Functioning, Brief Psychiatric Rating Scale derived from PANSS Total and Core, Clinical Global Impression (CGI)-Severity and CGI-Improvement. For the change in PANSS Negative Subscale score, a ratio to assess the equivalence of the treatment groups was calculated from the least squares mean changes from baseline, with equivalence claimed if the lower limit of the 95% confidence interval of the ratio exceeded 0.60. Mean daily dose, adjusted for differential numbers of subjects and differential days between visits, was 118.0 mg for ziprasidone and 144.7 mg for amisulpride. Mean PANSS Negative Subscale scores improved over the 12-week treatment period for intent-to-treat subjects, evaluable subjects (subjects with >or=4 weeks of double-blind treatment and no protocol deviations) and completers in both treatment groups. Ziprasidone demonstrated efficacy comparable to amisulpride in improving negative symptoms and global psychopathology. The groups demonstrated comparable improvements in secondary efficacy variables. Both agents were generally well tolerated, with comparably low incidences of movement disorders. In subjects with negative symptom-prominent schizophrenia, ziprasidone in mean daily doses of 118 mg was equivalent to amisulpride in mean daily doses of 148 mg in ameliorating negative symptoms and comparable in improving overall psychopathology and global illness severity.