Neither attention deficit hyperactivity disorder (ADHD) nor medications used to treat it have a long-term impact on kids’ growth, a new study published online in The Journal of Pediatrics suggests.

Previous studies have shown that medication may make kids with ADHD eat less and grow slower than their peers without the condition - at least at first. According to the Centers for Disease Control and Prevention, almost 10 percent of boys and 6 percent of girls have been diagnosed with ADHD.

“There have been concerns in the literature about the use of ADHD medications and their effect on growth,” Dr. Stephen Faraone, a psychiatrist at Upstate Medical University in Syracuse, New York, and one of the study’s authors, told Reuters Health. “We found that that (growth) delay tends to be most prominent in the first year or so, and tends to attenuate over time.”

Dr. Faraone and his colleagues measured and weighed 261 kids with and without ADHD that they had been following for at least ten years. Most of the kids with ADHD had spent at least some of that time on stimulants, such as Ritalin and Adderall.

At the end of the study, there was no difference in the height or weight of the kids - now mostly adults - who had ADHD and those that didn’t. There was also no relationship between their height and weight and how long they had been on medication, if at all.

Stimulant drugs are the most popular treatment for ADHD and are FDA approved for this purpose. The FDA has also approved non-stimulant drugs, which are not thought to affect growth. In addition to or instead of taking medications, many kids with ADHD get behavioral therapy and special help in the classroom.

Stimulants have been shown to delay growth when kids take them for a long time. The medications make some kids less hungry and might affect bone growth or the release of certain hormones that influence height. But this study supports growing evidence that those effects might balance out over the long term.

“I think that’s the general opinion, that there is maybe a temporary effect when you start treatment and then it goes away,” Dr. James Swanson, director of the Child Development Center at the University of California, Irvine, told Reuters Health. “That’s what this study essentially supports.”

All of the study’s authors have relationships with drug companies, some of which make stimulants. The lead author, Harvard University’s Dr. Joseph Biederman, was once called out by Iowa Senator Charles E. Grassley for the consulting fees he has received from such drug makers. The current study was funded by the government, a philanthropic fund, and the Eli Lilly and Company Foundation.

Swanson, who was not involved in the research, said that any long-term follow-up study like this one will lose some of its original subjects along the way, which could affect the results. The authors also point out that they couldn’t weigh and measure all the kids before they started taking medication, and they didn’t always know what dose of those medications kids were on.

Still, Swanson said, the study is interesting because it raises these questions, which can be addressed with further research. And to follow these kids for ten years, he said, was a substantial and significant effort.

SOURCE:

The Journal of Pediatrics, published online June 7, 2010.