By Ray Hainer
WEDNESDAY, November 10 (Health.com) — Nearly 1 in 10 children in the U.S. has been diagnosed with attention deficit hyperactivity disorder (ADHD), and the rate appears to be growing, according to a report released today by the Centers for Disease Control and Prevention (CDC).
The percentage of children ages 4 to 17 who have ever been diagnosed with ADHD rose from 7.8% to 9.5% between 2003 and 2007—a 22% increase, the CDC found. The report was based on the results of the National Survey of Children's Health, a nationwide telephone survey of parents.
The increases were especially dramatic among 15- to 17-year-olds and Hispanics.
It's unclear from the survey data whether the increase in diagnoses is due to an actual rise in ADHD cases stemming from social or environmental factors, or to growing awareness of the disorder, the researchers say.
Susanna Visser, an epidemiologist at the CDC and the lead author of the report, says that factors including lead exposure, low birth weight, and premature birth have all been shown to contribute to ADHD symptoms. "This collection of risk factors could be moving in a direction that causes certain demographic groups to have higher rates of ADHD," she says. "We have to figure out what's driving the change."
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Getting to the root of ADHD trends will require studies that follow groups of children over time, as well as genetic and MRI studies, Visser says. Several such studies are already under way at the National Institutes for Health, she adds.
Although ADHD rates went up in all 50 states, the increases were especially striking in 12 states, including Indiana, North Carolina, and Colorado. In North Carolina—which had the highest ADHD prevalence in the nation—the rate rose from 9.6% to 15.6%, an increase of about 63%.
Those 12 states "largely account for the increase" nationwide, Visser says.
States with very high diagnosis rates included Alabama (14%), Delaware (14%), Ohio (13%), West Virginia (13%), and Arkansas (13%), in addition to North Carolina.
Roughly half of all children diagnosed with ADHD had a "moderate" or "severe" case of the disorder, and two-thirds of all children with ADHD were taking medication to control it. The estimated 2.7 million children ages 4 to 17 taking ADHD drugs represent 5% of all children nationwide in that age group, according to the report.
If parents are concerned about their child's behavior, they should seek out information about ADHD and consult a doctor, Visser says. "There are ways to manage and control the symptoms of ADHD, through work with your doctor and with school professionals. This can be successfully managed."