Study of stimulant therapy raises concerns

The first long-term effort to track stimulant therapy in a large population of children has generated disturbing results. In particular, the North Carolina-based study finds that most 9-to-16-year-olds receiving Ritalin or other stimulants don’t exhibit attention-deficit hyperactivity disorder (ADHD), the only condition for which such drugs are approved.

More encouraging, about 3 of 4 kids who were diagnosed with ADHD on the basis of parents’ behavioral reports received stimulants, says a team led by psychiatric epidemiologist Adrian Angold of Duke University Medical Center in Durham, N.C. Youngsters with ADHD often benefit from these medications, especially if also given behavioral training (SN: 12/18&25/99, p. 388: http://www.sciencenews.org/sn_arc99/12_18_99/fob1.htm). Still, more than half of all stimulant users in the study fell short of even a relaxed definition of ADHD.

Children prescribed a stimulant typically took it for more than 3 years, regardless of their psychiatric status, the researchers note. Stimulant treatment helped kids with ADHD but had no effect on parent-reported symptoms of inattention or hyperactivity that didn’t qualify as ADHD. However, children taking these drugs proved more likely than the others to exhibit muscle tics, a side effect of prolonged stimulant use.

The prevalence of stimulant treatment among all the children doubled over 4 years to nearly 10 percent, supporting other evidence from medical databases of rises in numbers of stimulant prescriptions. “Our findings [also] suggest that current treatment practice in the community is far from optimal,” the researchers contend in the August Journal of the American Academy of Child and Adolescent Psychiatry.

“The system for the treatment of ADHD among children and adolescents is broken,” comments psychiatrist Kelly Kelleher of the University of Pittsburgh.

Angold’s team recruited 1,422 children, ages 9 to 13, from public schools in largely rural parts of western North Carolina’s Great Smoky Mountains. Annual psychiatric interviews with children and collection of data from parents occurred from 1992 to 1996. By then, data were available for participants up to age 16.

Ninety-two of the children displayed ADHD, the scientists say. Another 63 kids met criteria for a less severe version of the disorder. Of the 168 children receiving stimulants during the study, one-third had full-blown ADHD and fewer than one-tenth exhibited the milder form.

That leaves more than half of the stimulant-treated kids as never having had ADHD. Many children not treated with stimulants had as many or more ADHD symptoms as those who took the medication but didn’t have ADHD.

Among those with ADHD, a much larger proportion of boys and 9- to 12-year-old children received stimulants than did girls and older children. The latter two groups may get too little stimulant treatment, the researchers suggest.

Stimulant treatment of children without ADHD occurred half as often among children living in poor households as among those in families above the federal poverty line.

In the same journal, Peter S. Jensen, a psychiatrist at Columbia University, calls the new study “a masterful achievement.” Nonetheless, by relying only on parent reports and not teacher ratings, Angold’s group probably underestimated ADHD rates, Jensen holds. He’s concerned that many children with ADHD get either no or inadequate stimulant treatment (SN: 8/7/99, p. 90).

Evidence of extensive stimulant treatment among children who don’t have ADHD is “surprising and perplexing,” remarks psychiatrist Benedetto Vitiello of the National Institute of Mental Health in Bethesda, Md. Researchers should do larger studies of kids in different communities to probe this issue, he says.

Bruce Bower

Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.

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