ADHD Drugs Linked to Later Weight Gain in Kids
Study found 'rebound' effect in children who stopped using stimulants, which may increase obesity risk later
That makes sense, Schwartz said, because stimulants often cause kids to lose their appetites, which might initially lead to weight loss and decreased growth.
But by age 15 to 18, Schwartz noted that the growth picture had changed. By their late teens, kids who had taken and then stopped using stimulants tended to be one or two BMI points larger than their peers.
For an 18-year-old who stands 5 feet 7 inches, that's a 6- to 13-pound difference -- enough to tip a kid from being normal to overweight.
"As an average effect size, this is large," Schwartz said. "In contrast, in the untreated ADHD children, the effects are relatively small."
The study echoes previous research that has suggested a link between ADHD and obesity. But it doesn't prove ADHD medications by themselves cause kids to gain more weight.
Because children who were diagnosed with ADHD but left untreated also gained more weight than their peers without attention problems, it suggests that something about the disorder itself might also be to blame.
For example, the brains of people with ADHD don't process rewards the same way as others, said Dr. Tonya Froehlich, a developmental-behavioral pediatrician at Cincinnati Children's Hospital Medical Center in Ohio.
"There's a lot of reward that we get from eating -- especially things that are bad for us," Froehlich said. "If you have issues regulating reward and also regulating your delay of gratification, which we see a lot with ADHD, it makes sense that would also be linked to eating the wrong things at the wrong times and gaining more weight."
Froehlich said it will be important for parents to weigh the risks and the benefits of stimulants, including the possibility of rebound weight gain.
"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 risk may be worth it because they're having so many social and academic impairments," Froehlich said.