Roughly 6.4 million American children aged 4 through 17 have been diagnosed with ADHD—or about 11% of all children, according to new figures from the CDC, which shows that diagnoses for the disorder have exploded in the last decade. The problem is particularly pronounced among boys, nearly one in five of whom have been diagnosed with the disorder by the time they graduate high school, the New York Times reports. The numbers are up 16% since 2007 and 53% over the past 10 years.
While some see the numbers as a good sign that the disorder is being more widely recognized, many suspect over-diagnosis is at work. "Those are astronomical numbers. I'm floored," says one pediatric neurologist. "Mild symptoms are being diagnosed so readily, which goes well beyond the disorder and beyond the zone of ambiguity." And the numbers are only likely to grow, because the American Psychiatric Association is planning to broaden the definition of ADHD, making it easier to diagnose patients and prescribe them drugs. (Read more ADHD stories.)