Risperidone-associated weight gain in children and adolescents: a retrospective chart review

Risperidone use has been associated with substantial weight gain in children and adolescents. Reports available to date have consisted of small case series evaluated without standardized indices of developmentally normative weight increase. The purpose of this study was to evaluate age- and gender-adjusted weight changes linked to risperidone use in a juvenile psychiatric inpatient population.

Thirty-seven child and adolescent inpatients treated with risperidone for 6 consecutive months were compared to a group of 33 psychiatric inpatients with no atypical neuroleptic exposure. Weight, height, and body mass index (BMI) were recorded on at least a monthly basis, and Tanner staging was completed on admission. Percent change from baseline weight, changes in standardized z scores of weight for age and gender, and proportion of subjects experiencing a < or = 7% weight increase from baseline were compared among groups.

Subjects in both groups were comparable at baseline except for gender distribution (more males were in the risperidone group, p < 0.05). Risperidone-treated children and adolescents experienced significant weight gain between baseline and endpoint (paired t test, p < 0.001) that was first evident within 2 months of starting treatment, progressed steadily at an average rate of 1.2 kg/month, and did not reach a clear plateau during 6 months of observation. Significant increases in standardized weight were noted at 3 and 6 months for risperidone-treated subjects. Risperidone use conferred a substantial risk of gaining over 7% from baseline weight (odds ratio = 3.5, 95% confidence interval = 1.8-6.6, p < 0.001).

Six-month exposure to risperidone was associated with clinically significant weight gain in 78% of treated children and adolescents (as opposed to 24% of those in the comparison group, p < 0.001). Risperidone dosage, concomitant medication use, and other demographic characteristics such as age, pubertal status, gender, and baseline weight and BMI were not associated with an increased risk of morbid weight gain. Standardized z scores offer advantages for the assessment of weight change among developing children and adolescents.