Attention deficit hyperactivity disorder (ADHD) is the most commonly diagnosed mental disorder among children in the United States -- and a new analysis suggests that diagnoses are on the rise.
Between 2003 and 2011, the prevalence of ADHD diagnoses jumped by 43 percent among children between the ages of 10 and 14 and by 52 percent among 15- to 17-year-olds, according to parents who responded to a national survey conducted by the Centers for Disease Control and Prevention.
Although the overall rates remained highest among white children, the new analysis of the survey data, published in The Journal of Clinical Psychiatry on Tuesday, revealed that a growing number of Hispanic and black children are being diagnosed with the disorder.
And while ADHD has long been perceived as a boys' condition, researchers noted a surprising jump in diagnoses among girls, which increased by 55 percent during the study period.
The question of why, however, is one researchers say they do not have an answer for.
"This is speculative, but what [we are learning] is that the symptoms of females with ADHD may not be the same, so they may have been overlooked," Sean Cleary, an associate professor of epidemiology and biostatistics at Milken Institute School of Public Health at the George Washington University and one of the authors on the study, told The Huffington Post. "They may be more withdrawn, more internalizing."
Even girls who display "classic" symptoms of ADHD, such as restlessness and impulsivity, may have been missed in the past simply because many parents, teachers and doctors have operated under the misapprehension that ADHD rarely affects girls.
In general, Cleary said it is not yet clear whether the increasing rates are evidence of doctors doing a better job truly capturing how many children have the disorder; if the disorder is being over-diagnosed; or if something else is at play. Many experts have been critical of how readily ADHD diagnoses are handed out, and how quick some healthcare providers are to prescribe medications. For example, one CDC investigation found that thousands of toddlers are being medicated for ADHD with drugs like Ritalin and Adderall, despite the fact that the American Academy of Pediatrics does not even talk about diagnosing children under age 3.
But as researchers continue to probe possible factors driving the apparent increase, a key takeaway from the new study, Cleary said, is that caregivers and clinicians should zero in on potential symptoms among previously overlooked populations, including girls.
"If symptoms are being missed because of problems with accessing care, or because they're just not being recognized," he said, "that's important."
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