UC Berkeley News


New study finds use of ADHD medications has soared internationally
Evidence mounts that the disorder is 'not just a figment of U.S. doctors' imaginations'

| 07 March 2007

The use of psycho-stimulant drugs to treat attention-deficit/hyperactivity disorder (ADHD) has more than tripled worldwide since 1993, challenging widespread assumptions that this neuro-developmental disorder is concentrated in the United States, according to a new study from Berkeley researchers.

According to its authors, the findings, which reflect global trends, make a strong case for further studies on the long-term benefits of ADHD medications, as well as for an international exchange of ADHD data to better determine effective monitoring and treatment of this disorder.

The study, "The Global Market for ADHD Medications," published on Tuesday, March 6, in the journal Health Affairs, examined the use of such medications among 5- to 19-year-olds in countries belonging to the Organization for Economic Cooperation and Development (OECD), whose members are primarily North American, European, and northeast Asian nations.

Roughly one in 25 children and adolescents in the United States is taking medication for ADHD, says lead author Richard Scheffler, Distinguished Professor of Health Economics and Public Policy and director of the campus's Nicholas C. Petris Center on Health Care Markets and Consumer Welfare.

"Given the global diffusion of ADHD medications, as well as the prevalence of this condition, ADHD could become the leading childhood disorder treated with medications across the globe," Scheffler says. "We can expect that the already burgeoning global costs for medication treatment for ADHD will rise even more sharply over the next decade."

ADHD is characterized by poor concentration, distractibility, hyperactivity, impulsiveness, and other age-inappropriate symptoms. If untreated, it can result in learning difficulties, volatile peer relationships, and poor organizational skills.

Although the United States undeniably leads the world in spending on ADHD medication ($2.4 billion in 2003), growth trends indicate that other countries are following in its tracks, according to the study. For example, global spending on ADHD medications increased nine-fold among OECD countries during the time period studied - an increase due largely to the advent and availability of more costly and long-acting medications such as Concerta, Strattera, and Adderral XR, the study says.

"ADHD-medication treatment globally is becoming similar to that seen in the United States," says study co-author Peter Levine, a pediatrician with Kaiser Permanente in Walnut Creek. "But outside this country it is still primarily the less expensive, short-acting stimulant medications that are used. Costs are likely to rise globally as long-acting medications, which offer easier use and result in better compliance, become more prevalent outside the U.S."

Researchers looking at data from nearly 70 countries found that between 1993 and 2003 the number of countries using ADHD medications rose from 31 to 55, with the U.S. share of the global market decreasing from 86.8 percent to 83.1 percent. Meanwhile, nations with traditionally low and moderate consumption of ADHD drugs were showing steady upswings.

The results temper some key criticisms of ADHD, says Stephen Hinshaw, chair of the Department of Psychology and another co-author of the study.

"A common misconception is that ADHD exists only in the United States and that the pharmaceutical firms are getting bigger sales because of the 'creation' of the disorder in the U.S.," says Hinshaw, who investigates ADHD in children and adolescents. "Yet cross-cultural research has shown that ADHD exists in all cultures, with increased access to public education a factor in its detection. Clearly, ADHD - which has a substantial genetic liability - is not just a figment of American doctors' imaginations."

Although stimulant medications such as methylphenidate and dextroamphetamine can be abused because of their ability to improve study skills and trigger euphoria, Hinshaw says, that abuse is marginal in comparison to the valid therapeutic use of the drugs. Still, he cautions, careful diagnosis and careful monitoring of medications are essential, and behavioral treatments are also a viable alternative or complement to medication intervention.

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