Weight gain associated with antipsychotic drugs.

Weight gain has been reported with nearly every antipsychotic drug on the market (molindone is an exception). Weight gain occurs no matter what the patient's age, sex, or race and is seen with both oral and depot drug formulations. Numerous studies have found that patients gain weight when treated with a conventional antipsychotic, such as chlorpromazine, fluphenazine, and haloperidol. The newer, novel antipsychotics offer advantages over conventional antipsychotics, especially a relative lack of extrapyramidal symptoms, but some still have the disadvantage of causing weight gain. Clozapine and olanzapine in particular appear to cause substantial weight gain, much more so than do most conventional neuroleptics and novel agents such as risperidone. Given the risks to health and treatment compliance associated with weight gain and obesity, clinicians should monitor weight during the course of antipsychotic therapy and consider switching agents if excessive weight gain occurs.