Differential efficacy of risperidone versus haloperidol in psychopathological subtypes of subchronic schizophrenia

The aim of this study was to evaluate the efficacy and tolerability of risp eridone versus haloperidol in subchronic schizophrenia, using psychopatholo gical subgroups of patients with negative or positive and mixed symptoms to analyse the possible differential efficacy of the drugs. A total of 33 pat ients diagnosed using DSM-IV criteria entered the 6 week double-blind study with either risperidone or haloperidol 5 mg/day. Twenty-nine patients comp leted at least 2 weeks of treatment and entered the last observation carrie d-forward analysis. Both treatments were effective in reducing total scores and positive and negative subscale scores on the Positive and Negative Sca le for Schizophrenia (PANSS), with a significantly better extrapyramidal pr ofile in the risperidone-treated group. When analysis was repeated in each treatment group by psychopathological subtype (negative vs positive-mixed s ubgroups based on the PANSS composite index), risperidone was significantly superior to haloperidol in the intention to treat analysis in the negative subgroup. Repeated measures multivariate analysis of variance showed a sig nificantly greater improvement in the PANSS negative subscale scores of ris peridone-treated patients in the negative subgroup and a significant improv ement in the PANSS positive subscale scores in both psychopathological subt ypes. Haloperidol was significantly effective only in reducing positive sym ptoms in the positive subtype. Our results indicate that risperidone may be proposed for first-line treatment of subchronic schizophrenia, in particul ar the negative subtype. Copyright (C) 2001 John Wiley & Sons, Ltd.