Stimulant medications used to treat children with attention deficit hyperactivity disorder (ADHD) could be linked to weight gain during their teenage years, according to a recent study Reuters reported.

Researchers from the John Hopkins University Bloomberg School of Public Health found that children treated with ADHD stimulant medication experienced slower body mass index (BMI) growth than their undiagnosed or untreated peers, followed by a rapid rebound of BMI that could continue to obesity, Reuters reported.

"Our findings should motivate greater attention to the possibility that longer-term stimulant use plays a role in the development of obesity in children," Brian S. Schwartz, lead author of the study, said in a statement. "Given the dramatic rise in ADHD diagnosis and stimulant treatment for it in recent decades, this is an interesting avenue of research regarding the childhood obesity epidemic, because the rises in each of these roughly parallel one another."

For the study, researchers analyzed the electronic health records of 163,820 children, ages 3 to 18, in the Geisinger Health System, a Pennsylvania-based integrated health services organization. They compared the BMI trajectories of those who had never had a diagnosis or prescription (the "controls") with three groups: 1) those with a diagnosis but no stimulant prescription; 2) those with orders for stimulants without an ADHD diagnosis and 3) those with both an ADHD diagnosis and stimulant orders.

Those in group 3 had slower rates of BMI growth in early childhood, with more rapid rates during adolescence that eventually exceeded those of the controls. Those with a diagnosis of ADHD but no stimulant orders had more rapid BMI growth after age 10 versus the controls, but the effects were small.

"Stimulant use was strongly implicated," Schwartz said. "The earlier stimulants were started and the longer they were used, the stronger was their influence on the degree of both the delayed BMI growth in early childhood and the rebound BMI growth in late adolescence. This is an important unintended consequence of stimulant use in childhood."

ADHD is one of the most common pediatric disorders, with a 9 percent prevalence among children in the U.S., and ADHD medication is the second most prescribed treatment among children.