Body mass index change in autism spectrum disorders: comparison of treatment with risperidone and aripiprazole.

Objective: The purpose of this study was to assess change in body mass index (BMI) and age- and gender-adjusted BMI Z-score in subjects ages 2-20 years with autism spectrum disorders (ASD), who were treated longitudinally with risperidone or aripiprazole at a tertiary care ASD clinic.

Method: As part of a larger project involving longitudinal drug treatment data in ASD, detailed demographic and treatment data were collected for 142 subjects ages 2-20 years who had been started on risperidone or aripiprazole for treatment of irritability. Mean age at start of treatment, treatment duration, final Clinical Global Impressions-Improvement Scale score, BMI change per year of treatment, and BMI Z-score change per year of treatment (primary outcome measure) were calculated for each drug treatment group. Group means were compared using t tests and Wilcoxon rank sum tests.

Results: There was a statistically significant BMI and BMI Z-score increase in the risperidone and aripiprazole treatment groups individually. No statistically significant difference between the two treatment groups was noted in mean BMI change per year of treatment or BMI Z-score change per year of treatment.

Conclusions: In our review of long-term naturalistic treatment of irritability using risperidone versus aripiprazole in persons with ASD, a significant increase in both BMI and age- and gender-adjusted BMI Z-score was noted for each treatment group. No significant difference in BMI or BMI Z-score change was noted when the two treatment groups were compared. We conclude that in our patient population at a tertiary care ASD clinic, the effects of risperidone and aripiprazole on body weight gain in naturalistic long-term treatment are no different.