Treatment-resistant schizophrenia: clinical experience with new antipsychotics

Approximately 20-30% of patients with schizophrenia are resistant to conventional neuroleptics (i.e. are treatment-resistant). Clozapine has been shown to be effective in a proportion of treatment-resistant cases and to have a low side effect profile. However, it can cause agranulocytosis, is sedative and has marked anticholinergic properties. Risperidone, which is effective in chronic schizophrenia and has a low side effect profile and does not require routine blood monitoring, was compared with clozapine in a double-blind comparative study in 86 treatment-resistant patients. Preliminary findings indicate that, at endpoint, risperidone and clozapine were almost equieffective (total PANSS, PANSS subscales and CGI). Both drugs caused few adverse effects, and the severity of extrapyramidal symptoms was no different in the two groups. It is concluded that risperidone could be another drug effective in treatment-resistant schizophrenia. Further, larger trials will be needed to confirm this.