Children with attention-deficit hyperactivity disorder (ADHD) who are treated with stimulant medications are at risk for gaining more weight than their peers as they enter their teen years, according to a study published in the March 17 online Pediatrics.
The Centers for Disease Control and Prevention (CDC) reports that in 2011, 11 percent of U.S. children ages 4-17 had been diagnosed as having ADHD. With growing evidence linking the disorder to obesity, researchers, led by Brian Schwartz, a professor of environmental-health sciences, epidemiology and medicine at Johns Hopkins University Bloomberg School of Public Health, undertook a study to determine why hyperactive kids were prone to weight gains.
Schwartz and his colleagues analyzed data from the electronic health records of 163,820 children aged 3 to 18 and followed them over a period of up to 13 years. The researchers tracked diagnoses, drug treatments, and weight, looking at the children’s body mass index (BMI) – calculated as a measure of height and weight – in relation to ADHD diagnoses.
The researchers found that kids with ADHD who took stimulants to control their symptoms were thinner early on, and lagged behind their non-ADHD peers on growth charts. This finding was in keeping with accepted knowledge that stimulants can cause loss of appetite.
What surprised Schwartz and his team was that as the kids entered their late teens and stopped taking stimulants, they experienced “rebound” weight gains, adding pounds long after ceasing treatment. This group was one or two BMI points larger – six to eight pounds heavier – than their peers.
“As an average effect size, this is large,” Schwartz told HealthDay. “In contrast, in the untreated ADHD children, the effects are relatively small,” he added.
Study findings, say the researchers, suggest that there might be something about the drugs themselves that lead to weight gain.
“The reason we think it is more likely to be the drugs than the diagnosis is because the earlier the drugs were started and the longer the drugs were used, the stronger the effects,” explained Schwartz.
“If you agree with the reports that simulants may be over-prescribed, then this is another important cost of that over-treatment – kids who have dramatic changes in their growth trajectories during and after treatment,” said Schwartz.
The study, however, does not prove that treatment with stimulants causes obesity in ADHD kids, and one expert who was not involved in the study cautions parents to weigh the risks and benefits of the drugs.
“I think many children who have rip-roaring ADHD are having so much impairment from it that even if, when they stop taking their meds, they get this BMI rebound, as a parent that may worth it because they are having so many social and academic impairments,” advised Tonya Froehlich, MD, a developmental–behavioral pediatrician at Cincinnati Children’s Hospital Medical Center in Ohio.