Weight gain with risperidone among patients with mental retardation: Effect of calorie restriction

Background: The atypical antipsychotics cause weight gain, which is poorly understood in terms of its mechanism and treatment. A usual recommendation for treatment of antipsychotic-induced weight gain includes calorie restriction and exercise. The authors describe their recent clinical experience with calorie restriction in adults with mental retardation treated with risperidone. Method: A retrospective chart review was performed on the records of 50 adult patients with mental retardation treated with risperidone while residing at a habilitation center. We assessed dose and duration of risperidone treatment, weight, changes in calorie intake, and frequency of aggressive behavior. Results: Of the 50 patients, 39 had adequate data for analysis. Thirty-seven of the 39 patients gained weight with a mean of 18.8 lb (8.3 kg) over about 2 years. Twenty of the 37 patients were calorie restricted. Three of the 20 calorie-restricted patients lost weight at a rate of 0.2 lb (0.1 kg) per month. The other 17 calorie-restricted patients and the 17 patients who were not calorie restricted continued to gain weight at a rate of 0.8 lb (0.4 kg) per month over about another 2 years of treatment. The amount of weight gain was not dose related. Calorie restriction led to no deterioration in behavior. Conclusion: The current investigation lends support to data that note weight gain with risperidone in adults with mental retardation. It suggests that calorie restriction does not lead to weight loss or behavioral deterioration and that weight gain is not dose related.