Why estimates about the number of kids with ADHD vary
Doctors and researchers use many different methods to determine whether someone has ADHD or not. So the resulting stats can vary a lot.
How many kids in the world have ? Estimates of how many kids have ADHD vary widely, says Sheldon Horowitz, a learning disabilities consultant who served as director of LD resources at the National Center for Learning Disabilities.
One journal says 7 percent. Another says 3.4 percent. The CDC’s most recent U.S. estimate is 11.4 percent.
It’s very confusing for parents.
There’s a simple reason the numbers vary, however. These studies are based on research that uses many different ways to determine who has ADHD.
“The incidence of ADHD is very much influenced by the way in which it was identified,” Horowitz says.
Some doctors determine a child has ADHD based on how parents and teachers describe the child’s behavior. Others do so by observing the child over time or even in a brief office visit. Still others may decide a child has ADHD based on how the child responds to medication.
But there’s no set way to decide whether a child has ADHD. “There’s no blood test, brain scan, no X-ray, and no definitive way to say whether you’re in or out,” Horowitz says. “There is no screening other than the doctor’s eyes on the kid and what behaviors they choose to rule in or rule out.”
Horowitz says doctors often use one of half a dozen or so questionnaires to help screen for ADHD. Commonly used questionnaires include the Vanderbilt, the Conners, and the Achenbach. But the criteria differ in each.
The result is that we have many different estimates of how many kids have ADHD. And a big problem with that is that it leaves parents and teachers uncertain.
“If I’m a parent, I’m going to say, ‘How can I know for sure if my child has ADHD?’” says Horowitz. “I’m going to want to know a lot more before I even make a request for my kid to be evaluated.”
But this problem may be solved someday soon. Neuroscientists and medical researchers are starting to take a closer look at ADHD. They want to find out how best to identify and treat it.
“All of those areas of research and inquiry are getting to a better place,” Horowitz says. And once everyone agrees about how to identify ADHD, figuring out how many kids have it should be easier.