The prescribed use of stimulant medications to treat attention deficit hyperactivity disorder (ADHD) rose steadily from 1996 to 2008, according to a study conducted by the National Institutes of Health (NIH) and the Agency for Healthcare Research and Quality (American Journal of Psychiatry, 2011).

ADHD is one of the most common childhood disorders. It can continue through adolescence and adulthood. Symptoms include difficulty staying focused and paying attention, difficulty controlling behavior and hyperactivity. The condition frequently is treated with stimulants such as methylphenidate (e.g., Ritalin), amphetamines (e.g., Adderall), or other types of medications. Behavioral therapies also can be effective.

During the 1990s, stimulant prescription use among youth increased significantly, going from a prevalence rate of 0.6 percent in 1987 to 2.7 percent in 1997. The rate stabilized around 2.9 percent in 2002. However, recent reports suggest the prescribed use of these medications and the diagnosis of ADHD have continued to rise. Based on the National Survey of Children's Health, conducted by the Health Resources and Services Administration, the percentage of children ages 4-17 diagnosed with ADHD increased from 7.8 percent in 2003 to 9.5 percent in 2007.

"Stimulant medications work well to control ADHD symptoms, but they are only one method of treatment for the condition," said co-author Benedetto Vitiello, MD, of the National Institute of Mental Health. "Experts estimate that about 60 percent of children with ADHD are treated with medication."

For the current survey Dr. Vitiello and Samuel Zuvekas, PhD, of the Agency for Healthcare Research and Quality, examined data from the Medical Expenditure Panel Survey, a nationally representative annual survey of U.S. households, to determine prescribed stimulant use among children under age 19 from 1996 to 2008. They found a slow but steady increase - from 2.4 percent in 1996 to 3.5 percent in 2008.The rate grew an average of 3.4 percent each year, which is substantially less than the growth rate between 1987 and 1996, which averaged about 17 percent per year.

Overall, prescription use among 6- to 12-year-olds was highest, from 4.2 percent in 1996 to 5.1 percent in 2008. But the fastest growth occurred among 13- to 18-year-olds, from 2.3 percent in 1996 to 4.9 percent in 2008. "This continuous increase among teens likely reflects a recent realization that ADHD often persists as children age. They do not always grow out of their symptoms," said Dr. Vitiello.

Prescription use among preschoolers remained very low (at 0.1 percent) from 2004 onward and decreased between 2002 and 2008, suggesting that stimulant use continues to be disfavored in very young children. Boys are three times more likely to be prescribed a stimulant than girls, and use among white children is higher than among black or Hispanic children (4.4 percent in 2008 among whites, compared to 2.9 percent in blacks and 2.1 percent in Hispanics). However, prescribed stimulant use is increasing among racial and ethnic minorities, suggesting greater recognition of ADHD and the acceptance of psychopharmacological treatment in these groups, the authors said.

In addition, rates were substantially lower in Western states compared to other regions of the nation, with no increase in recent years. This finding is consistent with other studies. In comparison, rates in the Northeast increased from 2.7 percent in 2002 to 4.6 percent in 2008.

"These persistent differences in prescribed stimulant use related to age, racial and ethnic background, and geographical location indicate substantial variability in how families and doctors approach ADHD treatment throughout the United States," said Dr. Zuvekas.

When comparing the rates of prescribed use with the estimated prevalence of ADHD diagnosis, it appears that many children with ADHD are not treated with stimulants, the researchers concluded. "The children with the most severe symptoms are more likely to be taking stimulants. Those with milder symptoms are more likely being treated with psychosocial treatments or other non-stimulant medications."