FRIDAY, March 23 (HealthDay News) -- In the past decade, the number of children receiving a diagnosis of attention-deficit hyperactivity disorder (ADHD) has risen by 66 percent, new research indicates.

In 2000, just 6.2 million physician office visits resulted in a diagnosis of ADHD. By 2010, that number had jumped to 10.4 million office visits.

"This study is really like a 10,000 foot aerial view of this issue," said study author Dr. Craig Garfield, an assistant professor of pediatrics and medical social sciences at Northwestern University in Chicago. "We looked at the trends in visits to doctors for ADHD over the last decade, and we were interested in overlaying some of the FDA's public health advisories and the introduction of new medications to see the effect on those trends."

The findings are published in the March/April issue of Academic Pediatrics.

ADHD is now a common condition in children and teenagers in the United States, according to background information in the study. The parent-reported incidence of the disorder is about 10 percent, or 5.4 million children. Symptoms of ADHD include an inability to focus, trouble controlling emotions and hyperactive behavior, according to the National Institute of Mental Health (NIMH).

Treatment for ADHD may include medications -- usually stimulant drugs -- and behavioral therapies, according to the NIMH. However, new medications -- and new health concerns -- altered treatment decisions over the decade studied.

In 2002, a nonstimulant medication, Strattera (atomoxetine), was approved for use in ADHD. In 2005, the U.S. Food and Drug Administration issued warnings that sudden death and suicidal thinking had been linked to Strattera. That same year, the FDA also expressed concern about a potential link between amphetamine-dextroamphetamine (Adderall) and cardiovascular risks, as well as adverse psychiatric symptoms. That same warning was extended to all approved ADHD medications in 2007, according to the study.

For their study, Garfield and his colleagues reviewed data from a national database from 2000 to 2010. They examined office visits for patients younger than 18.

In addition to finding a 66 percent increase in the number of office visits resulting in an ADHD diagnosis, they also found that more children were being treated for ADHD by child psychiatrists than by pediatricians. At the start of the study, about one in four children saw a psychiatrist for their condition. By the end of the study, more than one in three was visiting a psychiatrist for ADHD.

Despite possible concerns about safety, stimulant medications remain the mainstay of treatment. In 2000, 96 percent were treated with these medications, while 87 percent were receiving stimulant medication for their ADHD symptoms in 2010, the study found.

The use of Strattera, a nonstimulant drug, dropped from 15 percent in the year it was introduced (2002) to 6 percent by 2010. The use of other nonstimulant treatments, such as clonidine (Catapres/Kapvay/Nexiclon), guanfacine (Intuniv/Tenex) and Wellbutrin (buproprion), was relatively constant, but reached a high of 13 percent in 2010 following the introduction of extended-release Intuniv, the researchers found.

One previous study, published online last September in the American Journal of Psychiatry, found that about 2.8 million children were taking ADHD medications. Those authors said their use has risen gradually, likely because more teenagers are taking these medications.

The authors of the current study don't think there's suddenly been a dramatic rise in the number of children with ADHD, but instead believe that public awareness campaigns, media coverage of ADHD and advertisements for new medications are probably some of the driving factors behind the rise in diagnoses.

"There's more of an awareness on the part of the parents about this disease," said Garfield.

He said that the authors don't know why more people are taking their children to see psychiatrists for treatment, but said if the trend continues, parents may have trouble finding a doctor to care for their child's ADHD, given the shortage of psychiatrists.

Other experts agreed that the incidence of ADHD probably isn't going up that quickly. "I don't think these data reflect true prevalence. I think it's the total frequency of visits related to ADHD is going up," said Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at Steven and Alexandra Cohen Children's Medical Center of New York in New Hyde Park, N.Y.

"The American Academy of Pediatrics is encouraging pediatricians to play a more active role in the diagnosis and treatment of ADHD, so it's interesting to see that psychiatrists over time are now treating more," he said. "Pediatricians may be referring more, or as safety concerns have been raised by the FDA, it may be that families prefer to see a specialist."

More information

Learn more about ADHD from the U.S. National Institute of Mental Health.