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

Background Substantial weight gain is common with many atypical antipsychotics. Aims To 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. Method Survival 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 ast-observation-carried-forward (LOCF), observed cases and study completion approaches. Results After 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.=73) 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 halopericlol. Change in body mass index was significantly predicted only by treatment group (P < 0.0001). Conclusions Olanzapine was associated with significantly greater weight gain than haloperidol, with both leading to greater weight gain than previously described. Declaration of interest This work was financially supported by Lilly Research Laboratories. M.F.T. and G.DT are employees of Lilly Research Laboratories.