Factors Influencing Acute Weight Change in Patients With Schizophrenia Treated With Olanzapine, Haloperidol, or Risperidone

Objective: Clinical factors predicting weightchange in patients with schizophrenia and related disordersduring acute treatment with the antipsychotic drugs olanzapine,risperidone, and haloperidol were sought through retrospectiveanalyses.

Method: Six-week body-weight data from 2 trials,study 1 comparing olanzapine and haloperidol (N = 1369) and study2 olanzapine and risperidone (N = 268), were analyzed. Effects of8 clinically relevant covariates–therapy, clinical outcome(Brief Psychiatric Rating Scale), baseline body mass index(BBMI), increased appetite, age, gender, race, and dose–onweight were compared.

Results: In study 1, olanzapine (vs.haloperidol) therapy, better clinical outcome, lower BBMI, andnonwhite race significantly affected weight gain. Effects ofincreased appetite and male gender on weight gain weresignificant for olanzapine but not for haloperidol. In study 2,better clinical outcome, lower BBMI, and younger agesignificantly affected weight gain. Increased appetite was morefrequent during olanzapine treatment than during haloperidol, butnot significantly different from risperidone. Significantdifferences in effect on weight change were found betweenolanzapine and haloperidol but not between olanzapine andrisperidone. No evidence was found that lower antipsychotic drugdoses were associated with lower weight gain.

Conclusion: This report identifiespredictive factors of acute weight change in patients withschizophrenia. Similar factors across antipsychotic drugs inpredicting greater weight gain included better clinical outcome,low BBMI, and nonwhite race. Factors differing betweenconventional (haloperidol) and atypical (olanzapine) agentsincluded increased appetite and gender. Choice of atypicalantipsychotic drug (olanzapine vs. risperidone) was of minorimportance with regard to influence on acute weight gain.