Factors influencing acute weight change in patients with schizophrenia treated with olanzapine, haloperidol, or risperidone

Objective: Clinical factors predicting weight change in patients with schiz ophrenia and related disorders during acute treatment with the antipsychoti c drugs olanzapine, risperidone, and haloperidol were sought through retros pective analyses. Method: Six-week body-weight data from 2 trials, study 1 comparing olanzapi ne and haloperidol (N = 1369) and study 2 olanzapine and risperidone (N = 2 68), were analyzed. Effects of 8 clinically relevant covariates-therapy, cl inical outcome (Brief Psychiatric Rating Scale), baseline body mass index ( BBMI), increased appetite, age, gender, race, and dose-on weight were compa red. Results: In study 1, olanzapine (vs. haloperidol) therapy, better clinical outcome, lower BBMI, and nonwhite race significantly affected weight gain. Effects of increased appetite and male gender on weight gain were significa nt for olanzapine but not for haloperidol. In study 2, better clinical outc ome, lower BBMI, and younger age significantly affected weight gain. Increa sed appetite was more frequent during olanzapine treatment than during halo peridol, but not significantly different from risperidone. Significant diff erences in effect on weight change were found between olanzapine and halope ridol but not between olanzapine and risperidone. No evidence was found tha t lower antipsychotic drug doses were associated with lower weight gain. Conclusion: This report identifies predictive factors of acute weight chang e in patients with schizophrenia. Similar factors across antipsychotic drug s in predicting greater weight gain included better clinical outcome, low B BMI, and nonwhite race. Factors differing between conventional (haloperidol ) and atypical (olanzapine) agents included increased appetite and gender. Choice of atypical antipsychotic drug (olanzapine vs, risperidone) was of m inor importance with regard to influence on acute weight gain.