Antipsychotic polypharmacy in clozapine resistant schizophrenia: a randomized controlled trial of tapering antipsychotic co-treatment

There is a considerable disparity between clinical practice and recommendations based on meta-analyses of antipsychotic polypharmacy in clozapine resistant schizophrenia. For this reason, we investigated the clinical response to reducing the use olanzapine that had been previously added on clozapine treatment among seriously ill hospitalized patients. In a randomized controlled trial with crossover design, we studied volunteer patients (N=15) who had olanzapine added on to clozapine in a state mental hospital. Clozapine monotherapy was just as effective as clozapine-olanzapine therapy, according to results from Clinical Global Impression Scale and Global Assessment of Functioning as primary outcome measures. Polypharmacy is widely used in treating schizophrenia, and usually, add-on medications are started because of worsening of the clinical state. A major confounding feature of these add-ons is whether observed improvements are caused by the medication or explained by the natural fluctuating course of the disorder. The present study, in spite of its small size, indicates the necessity of reconsidering the value of polypharmacy in treating schizophrenia.