Review of atypical antipsychotics and weight gain.

Prescribing an antipsychotic for a patient with schizophrenia requires a risk-benefit analysis. Weight gain has become an issue recently as a result of reports that 2 of the atypical antipsychotic agents, clozapine and olanzapine, are associated with a higher risk than other drugs of causing excessive weight gain. Some degree of weight gain may occur with any atypical antipsychotic agent, particularly early in treatment. A more important consideration is the long-term effects of the atypical antipsychotic on body weight, since many of the patients in this population require chronic therapy. This is important because weight gain is an adverse effect that is associated with noncompliance and medical problems. In this article, I review recent reports about the weight effects of different atypical antipsychotic drugs. To provide accurate understanding of the effects of atypical antipsychotic agents, data analyses should include both short-term and long-term findings, the relationship of changes in body weight to pretreatment body mass index (BMI), relationship to dose, both intent-to-treat and complete analyses, and presentation of both mean and median changes in weight. It is also important to know whether the studies have been done in an inpatient or outpatient setting, since patients who are institutionalized may be less likely to exhibit increases in body weight. Such complete information and multidimensional analysis would minimize obfuscation about the true nature of a drug's impact on body weight.