The prescribed use of stimulant medications to treat attention deficit hyperactivity disorder (ADHD) rose slowly but 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 (AHRQ). The study was published online ahead of print September 28, 2011, in the American Journal of Psychiatry.
ADHD is one of the most common childhood disorders, and can continue through adolescence and adulthood. Symptoms include difficulty staying focused and paying attention, difficulty controlling behavior, and hyperactivity (over-activity). The condition is frequently treated with stimulants such as methylphenidate (e.g., Ritalin), amphetamines (e.g., Adderall) or other types of medications. Behavioral therapies can also be effective.
During the 1990s, stimulant prescription use increased significantly, going from a prevalence rate among youth of 0.6 percent in 1987 to 2.7 percent in 1997, with the rate stabilizing around 2.9 percent in 2002. Recent reports, however, suggest that the prescribed use of these medications and the diagnosis of ADHD have continued to rise. Based on the Health Resources and Services Administration's National Survey of Children's Health, the percentage of children age 4-17 years 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. Experts estimate that about 60 percent of children with ADHD are treated with medication," said co-author Benedetto Vitiello, M.D., of NIH's National Institute of Mental Health (NIMH).
For this most recent survey, Dr. Vitiello and Samuel Zuvekas Ph.D., of AHRQ examined data from the AHRQ-sponsored Medical Expenditure Panel Survey, a nationally representative annual survey of U.S. households, to determine prescribed stimulant use among children under age 19 from 1996-2008. 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 6-12-year-olds was highest, going from 4.2 percent in 1996 to 5.1 percent in 2008. But the fastest growth of prescribed use occurred among 13-18-year-olds, going 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 among very young children continues to be disfavored. Boys continued to be three times more likely to be prescribed a stimulant than girls, and use among white children continued to be 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, likely suggesting more recognition of ADHD and acceptance of psychopharmacological treatment among these groups, according to the authors.
In addition, rates were substantially lower in Western states compared to other regions of the nation, with no increase in recent years, a finding 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.
The researchers concluded that 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 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," they said.