Objective: To review systematically data relating to weight changes with atypical antipsychotics.
Method: We conducted a Medline search on October 29 1999 and covered the period 1980–99. All recovered papers were examined for further relevant reports. In addition, we wrote to pharmaceutical manufacturers and 10 practising clinicians to ask them to provide other relevant reports known to them.
Results: Eighty reports mentioning change in body weight were retrieved. Data relating to weight changes were of variable quality. Weight changes were indicated by a variety of measures. The majority of reports related to short-term changes.
Conclusion: All atypical drugs, with the exception of ziprasidone, have been associated with weight increases. Clozapine seems to have the highest risk of weight gain, followed by olanzapine and quetiapine. There is probably a lower risk with risperidone, sertindole and zotepine and a still lower risk with amisulpride. Ziprasidone appears not to be associated with weight gain. In the absence of more compelling data, these rankings must be considered approximate and preliminary. Longer, more robust trials are needed.