A review of the effect of atypical antipsychotics on weight.

Controlled research trials have shown that atypical antipsychotics have important advantages over standard antipsychotics, including a broader spectrum of efficacy and improved tolerability profile, particularly with regard to neurological adverse events such as extrapyramidal symptoms (EPS). Some atypical antipsychotics, however, tend to cause significant weight gain, which may lead to poor compliance and other adverse health effects. The mechanisms involved in antipsychotic drug-related weight gain are as yet uncertain, although serotoninergic, histaminic, and adrenergic affinities have been implicated along with other metabolic mechanisms. The atypical antipsychotics vary in their propensity to cause weight change with long-term treatment. Follow-up studies show that the largest weight gains are associated with clozapine and olanzapine, and the smallest with quetiapine and ziprasidone. Risperidone is associated with modest weight changes that are not dose related. Given the equivalent efficacy of atypical antipsychotics, weight-gain profile is a legitimate factor to consider when constructing an algorithm for treatment due to the serious medical consequences of obesity.