Weight gain in antipsychotic-naive patients: a review and meta-analysis.

BACKGROUND Weight gain is a long-recognized side-effect of antipsychotic (AP) drugs and a major health concern in the treatment of psychosis. The strength of the causal relationship between AP drug exposure and weight gain can only be gauged by a drugs trial conducted on AP-naive patients. METHOD We conducted a review of the literature regarding the amount of weight gain induced by APs in AP-naive patients and carried out a meta-analysis of mean weight gains. RESULTS We found 11 primary studies reporting the effects of APs on body weight or body mass index (BMI) in AP-naive patients. The mean body weight and BMI gains in AP-naive patients were highly significant from the first weeks of treatment. When we limited the analysis to studies conducted on patients hospitalized and without any adjunctive treatment potentially affecting weight, the resultant sample showed less heterogeneity and confirmed the final picture of weight gain at around 3.8 kg and 1.2 points BMI. CONCLUSIONS Weight gain associated with AP therapy in AP-naive patients occurs rapidly in the first few weeks and continues during the following months. Clinicians should be aware of the high probability of causing weight gain in AP-naive patients and should strictly monitor such patients.