Abstract
We conducted a secondary analysis of a completed study of the differential efficacy and side effects of aripiprazole versus haloperidol in early-stage schizophrenia (ESS), a subpopulation of patients which does not include first episode or chronic patients. A subpopulation of 360 individuals with ESS were identified from a randomized, multi-center, double-blind study of 1294 individuals with schizophrenia at different stages of illness who were randomized to treatment with aripiprazole (ESS = 237) or haloperidol (ESS = 123) for one year. The primary outcome measure was response rate based on a 50% reduction of Positive and Negative Syndrome Scale (PANSS) total scores. Secondary outcomes included several efficacy and safety measures, as well as treatment discontinuation. More individuals in the aripiprazole group (48%) than in the haloperidol group (28%; p < 0.01) completed the study. Response rates were greater in the aripiprazole group (38% [N = 91]) than in the haloperidol group (22% [N = 27]; p < 0.01). Aripiprazole was associated with fewer extrapyramidal side effects. ESS subjects in the haloperidol group were more likely than those in the aripiprazole group to discontinue the study drug due to an adverse event other than worsening illness (29% and 11%, respectively; p < 0.01), and efficacy differences were reduced by interventions to mitigate side effects (decreasing antipsychotic dose with or without adding antiparkinsonian medication). Aripiprazole has a favorable efficacy/safety profile in ESS and appeared to be superior to haloperidol on a number of efficacy and safety outcomes. However, excessive dosing of the antipsychotic medications, in particular haloperidol, may have played an important role in accounting for the differences between aripiprazole and haloperidol in this study.