Objectives: The study investigates the risk of obesity for young children prescribed an atypical antipsychotic (AAP) for 6 months or more. AAPs are associated with risk of obesity. They are used in children for a variety of psychiatric conditions and are often prescribed off-label. Long-term risk of obesity in this age group is unknown as most studies are short-term investigations and generally combine younger children with adolescents and adults. Methods: A retrospective cohort of children, 10 years old or younger, prescribed either an AAP or selective serotonin reuptake inhibitor (SSRI) for 6 months or more were followed for up to 9.5 years. The primary endpoint was the body-mass index (BMI) reaching the 95th percentile. Results: One thousand six hundred fifty-five patients met inclusion criteria. One thousand one hundred eighteen patients were prescribed an AAP and 537 were prescribed an SSRI: 1152 (74.5%) patients were male and mean (standard deviation) age was 7.9 [1.90] years at study entry. Median follow-up was 3.58 years for the AAP cohort and 3.28 years for the SSRI cohort (p = 0.02). After adjusting for baseline demographic variables, BMI, and other concomitantly prescribed medications, children prescribed AAPs for 6 months or longer were twice as likely to become obese compared with children prescribed SSRIs (adjusted hazard ratio [HR] 2.06 [95% confidence interval; CI 1.60-2.66], p < 0.0001). Further stratification by AAP revealed that the obesity risk for patients prescribed aripiprazole was 34% greater than for those prescribed risperidone (adjusted HR 1.34 [95% CI 1.01-1.78], p = 0.0033). Conclusions: The risk of obesity for young children prescribed an AAP for 6 months or more is approximately double that of children prescribed an SSRI. The risk of obesity is greater with aripiprazole than risperidone in the first year. Prescribers should consider the risk of obesity when prescribing AAPs and consider alternative treatment modalities in this vulnerable patient population.
Keywords: SSRI; antipsychotic; child; obesity.