Adjunctive treatment with risperidone in clozapine-resistant schizophrenia: a case report and review

Long-term studies show that 47% to 63% of schizophrenic patients treated with clozapine fail to respond after 12 years of treatment. Such high rates of resistance justify the growing interest in therapeutic strategies based on enhancing the effect of clozapine with other antipsychotics. The combination of clozapine and risperidone in the treatment of partial responders to clozapine has been one of those receiving most interest from research.

The present work reports the case of a 26-year-old man, diagnosed with schizophrenia who, after treatment with clozapine at appropriate doses over 12 weeks without observable response, showed a marked and sustained improvement after the addition of risperidone to the clozapine treatment. We also present a detailed review of publications related to the therapeutic combination of clozapine and risperidone in clozapine-resistant schizophrenia.

Despite the contradictory nature of the published data, our results are in support of other work reporting that treatment with a combination of clozapine and risperidone, apart from being well tolerated, may constitute an effective alternative in this type of patient. Nevertheless, there is a need for further, controlled studies, with larger samples, with a view to drawing definitive conclusions and making specific recommendations.