A new study has sobering news for educators who have seen an
explosion in the number of students diagnosed with attention deficit
hyperactivity disorder in recent years: There may be even more children
with ADHD than previously thought.
The proportion of students being treated for the disorder could be "greatly underestimated," says the report released this month by the National Institute of Environmental Health Sciences, an arm of the National Institutes of Health and the University of North Carolina School of Medicine.
For the study, scientists surveyed parents and teachers in a "typical" county, with a mix of rural and suburban homes—Johnston County, N.C., near Raleigh, was their choice— if their children had ADHD and took medicine to treat the condition.
Previously, the U.S. surgeon general has estimated that the proportion of children ages 6 to 12 who have ADHD is 3 percent to 5 percent. But the new study shows that more than 15 percent of boys in grades 1-5 had been diagnosed. About 10 percent of the boys in the survey were taking medication for the condition. About 5 percent of girls surveyed had been diagnosed with ADHD.
The Johnston County results, assuming a roughly equal number of boys and girls in the schools, suggest that about 10 percent of elementary school students have ADHD. The inclusion of parents in the survey, in addition to educators, may account in part for the higher figures. School nurses, for example, may not always be aware of children who receive their medication treatment only at home, the report notes.
Experts have offered widely varying estimates on ADHD's prevalence. The American Academy of Pediatrics says between 4 percent and 12 percent of children between the ages of 6 and 12 have ADHD.
Parents and teachers of more than 6,000 children in 17 public elementary schools provided the basis for the Johnston County study. The percentages of students with ADHD who took medication differed across gender and racial lines. Boys were three times more likely than girls to be on medication, the study found. Also, even though similar proportions of black and white students were diagnosed as having ADHD, 8 percent of white children surveyed were receiving medication for treatment, compared with 5 percent of African-American children in the survey, the authors say.
The research is published in the February issue of the American Journal of Public Health, which can be viewed online at www.ajph.org.
—Lisa Fine [email protected]
Vol. 21, Issue 22, Page 17