Background: Available data on atypical antipsychotic-induced weight gain are limited by a number of methodological factors. The objective of this report is to evaluate short-term (N=1742) and long-term (N=1649) weight effects in patients receiving standard doses of amisulpride, haloperidol, olanzapine, risperidone, ziprasidone, and placebo based on 21 randomized, placebo-controlled, parallel-group studies from an integrated clinical trial database.
Method: Analyses of the integrated ziprasidone schizophrenia trials database were performed to estimate the weighted average of weight change and the percentage of subjects experiencing weight gain (or weight loss) across studies for each agent studied, based on fixed- and random-effects models. Durations of treatment exposure in long-term trials were controlled by well-defined time windows (6 month: 150 to 210 days; 1 year: 330 to 390 days). Weight gain or loss was defined using a 7% change from baseline threshold.
Results: During long-term therapy with 1-year treatment duration, incidence of weight gain for subjects treated with ziprasidone (17%) was not significantly different from the placebo (13%) or haloperidol (41%) groups based on 95% confidence interval. In contrast, significantly greater weight gain incidence was observed for the olanzapine (57%) and risperidone (39%) groups compared to placebo. Median weight change of +0.49, -0.18, +1.50 and +0.55 lb/month was observed for haloperidol, ziprasidone, olanzapine and risperidone subjects, respectively, indicating differential weight change patterns compared to placebo (-0.32). Similar results were observed for the short-term (4-12 weeks) and 6-month treatment exposure cohorts.
Conclusions: Our results confirm significant differences in long-term weight effects among atypical antipsychotics, consistent with findings from prior meta-analysis of antipsychotic-induced weight gain [Allison, D.B., Mentore, J.L., Heo, M., Chandler, L.P., Capelleri, J.C., Infante, M.C., Weiden, P.J., 1999. Antipsychotic induced weight gain: a comprehensive research synthesis. Am J Psychiatry 156, 1686-1696] and the CATIE schizophrenia study [Lieberman, J.A., Stroup, T.S., McEvoy, J.P., et al., 2005. Effectiveness of antipsychotic drugs in patients with chronic schizophrenia. N Engl J Med 353, 1209-1223].