Drugs treating attention deficit hyperactivity disorder in kids have no long-term benefits – and actually stunt their growth, a study shows.

A SUNY Buffalo study that tracked 600 kids since the early 1990s concluded that drugs like Ritalin and Concerta worked for a while, but not after three years.

Report co-author Dr. William Pelham said he believes earlier findings on the drugs’ effectiveness were overstated.

“I think that we exaggerated the beneficial impact of medication in the first study,” he told the BBC yesterday.

“We had thought that children medicated longer would have better outcomes. That didn’t happen to be the case.”

Instead, he said, the kids “had a substantial decrease in their rate of growth so they weren’t growing as much as other kids, both in terms of their height and in terms of their weight.

“In the short run, [medication] will help the child behave better, in the long run it won’t. And that information should be made very clear to parents,” he said.