ADHD Drug Does Stunt Growth
After 3 Years on Ritalin, Kids Are Shorter, Lighter Than Peers
July 20, 2007 - After three years on the ADHD drug Ritalin, kids are about an inch shorter and 4.4 pounds lighter than their peers, a major U.S. study shows.
The symptoms of childhood ADHD -- attention deficit hyperactivity disorder -- usually get dramatically better soon after kids start taking stimulant drugs. But this benefit may come with a cost, says James Swanson, PhD, director of the Child Development Center at the University of California, Irvine.
"Yes, there is a growth suppression effect with stimulant ADHD medications," Swanson tells WebMD. "It is going to occur at the age of treatment, and over three years it will accumulate."
Whether these kids eventually grow to normal size remains a question. Kids entered the study in 1999 at ages 7 to 9. The current report is a snapshot taken three years later. The 10-year results -- when the kids are at their adult height -- won't be in for two more years.
"The big question now is whether there is any effect on these kids' ultimate height," Swanson says. "We don't know if by the time they are 18 they will regain the height."
The finding appears to end decades of debate over whether stimulant medications affect children's growth. Less than 10 years ago, a National Institutes of Health panel concluded that the drugs carried no long-term growth risk.
That opinion was so widely accepted that the study authors -- who include most of the leading ADHD researchers in the U.S. -- did not warn parents that the study medication might carry this risk.
At the time, researchers thought that any short-term stunting of growth would be made up by a hypothesized "growth spurt" that would occur with continued treatment. But Swanson and colleagues saw no evidence of such a growth spurt.
Another widely accepted theory was that ADHD itself stunted kids' growth. But in a surprise finding, the study found that ADHD kids who do not take stimulant drugs are much larger than kids without ADHD. And these untreated kids continued to grow much faster than kids taking stimulant drugs.