The number of American children with attention deficit hyperactivity disorder is on the rise, according to new data from the U.S. Centers for Disease Control and Prevention.

More than 1 in 10 kids ages 4 to 17 has been diagnosed with ADHD and an increasing number of them are taking medication to address their symptoms, the CDC said.

The findings released Friday come from a survey of over 95,000 parents, which was conducted in 2011.

The agency found that about 11 percent of kids — or roughly 6.4 million — had been given a diagnosis of ADHD, which is characterized by difficulty paying attention or controlling impulsive behaviors.

By contrast, a similar survey put the number of children diagnosed with the condition at 9.5 percent in 2007 and 7.8 percent in 2003.

ADHD is more common among boys than girls, according to the latest CDC findings which were published online in the Journal of the American Academy of Child and Adolescent Psychiatry.

Of those with a current diagnosis, more than two-thirds were taking medication for the condition, the survey found.

It’s unclear if the increasing prevalence of ADHD is due to an actual uptick in cases or better recognition of the condition, CDC officials said.

ADHD is among the most common chronic conditions affecting children. A recent study found that almost one-third of children with autism also have ADHD.

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