Course and predictors of weight gain in people with first-episode psychosis treated with olanzapine or haloperidol

Abstract

BackgroundSubstantial weight gain is common with many atypical antipsychotics.AimsTo evaluate the extent, time course and predictors of weight gain and its effect on study retention among people with first-episode psychosis treated with olanzapine or haloperidol.MethodSurvival analysis assessed time to potentially clinically significant weight gain (⩾7%) and the effect of weight gain on study retention. Weight gain during the 2-year study was summarised using last-observation-carried-forward (LOCF), observed cases and study completion approaches.ResultsAfter 2 years of treatment, LOCF mean weight gain was 10.2 kg (s.d.=10.1) for olanzapine (n=131) and 4.0 kg (s.d.=7.3) for haloperidol (n=132); observed cases mean weight gain was 15.4 kg (s.d.=10.0) for olanzapine and 7.5 kg (s.d.=9.2) for haloperidol. Change in body mass index was significantly predicted only by treatment group (P < 0.0001).ConclusionsOlanzapine was associated with significantly greater weight gain than haloperidol, with both leading to greater weight gain than previously described.