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 risperidone versus haloperidol in subchronic schizophrenia, using psychopathological subgroups of patients with negative or positive and mixed symptoms to analyse the possible differential efficacy of the drugs. A total of 33 patients diagnosed using DSM-IV criteria entered the 6 week double-blind study with either risperidone or haloperidol 5 mg/day. Twenty-nine patients completed at least 2 weeks of treatment and entered the last observation carried-forward analysis. Both treatments were effective in reducing total scores and positive and negative subscale scores on the Positive and Negative Scale for Schizophrenia (PANSS), with a significantly better extrapyramidal profile in the risperidone-treated group. When analysis was repeated in each treatment group by psychopathological subtype (negative vs positive-mixed subgroups 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 significantly greater improvement in the PANSS negative subscale scores of risperidone-treated patients in the negative subgroup and a significant improvement in the PANSS positive subscale scores in both psychopathological subtypes. Haloperidol was significantly effective only in reducing positive symptoms in the positive subtype. Our results indicate that risperidone may be proposed for first-line treatment of subchronic schizophrenia, in particular the negative subtype. Copyright 2001 John Wiley & Sons, Ltd.