Aripiprazole versus haloperidol in combination with clozapine for treatment-resistant schizophrenia in routine clinical care: a randomized, controlled trial

This multi-site study was conducted to compare the efficacy and tolerability of combination treatment with clozapine plus aripiprazole versus combination treatment with clozapine plus haloperidol in patients with schizophrenia who do not have an optimal response to clozapine. Patients continued to take clozapine and were randomly assigned to receive daily augmentation with aripiprazole or haloperidol. Doctors prescribed the allocated treatments according to usual clinical care. Withdrawal from allocated treatment within three months was the primary outcome. Secondary outcomes included severity of symptoms on the Brief Psychiatric Rating Scale (BPRS) and antipsychotic subjective tolerability on the Liverpool University Neuroleptic Side Effect Rating Scale (LUNSERS). A total of 106 patients with schizophrenia were randomly assigned to treatment. After three months, we found no difference in the proportion of patients who discontinued treatment between the aripiprazole and haloperidol groups (13.2 vs 15.1%, p = 0.780). The 3-month change of the BPRS total score was similar in the aripiprazole and haloperidol groups (-5.9 vs -4.4 points, p = 0.523), while the 3-month decrease of the LUNSERS total score was significantly higher in the aripiprazole group than in the haloperidol group (-7.4 vs -2.0 points, p = 0.006). These results suggest that augmentation of clozapine with aripiprazole offers no benefit with regard to treatment withdrawal and overall symptoms in schizophrenia as compared with augmentation with haloperidol. However, an advantage in the perception of adverse effects with aripiprazole treatment may be meaningful for patients.