Study Finds Nearly 1 Million Kids Misdiagnosed with ADHD
August 17, 2010
Nearly 1 million children in the United States are potentially misdiagnosed with attention deficit hyperactivity disorder simply because they are the youngest — and most immature — in their kindergarten class, according to new research by a Michigan State University economist.
These children are significantly more likely than their older classmates to be prescribed behavior-modifying stimulants such as Ritalin, said Todd Elder, whose study will appear in a forthcoming issue of the Journal of Health Economics.
Such inappropriate treatment is particularly worrisome because of the unknown impacts of long-term stimulant use on children’s health, Elder said. It also wastes an estimated $320 million-$500 million a year on unnecessary medication — some $80 million-$90 million of it paid by Medicaid, he said.
Elder said the “smoking gun” of the study is that ADHD diagnoses depend on a child’s age relative to classmates and the teacher’s perceptions of whether the child has symptoms.
“If a child is behaving poorly, if he’s inattentive, if he can’t sit still, it may simply be because he’s 5 and the other kids are 6,” said Elder, assistant professor of economics. “There’s a big difference between a 5-year-old and a 6-year-old, and teachers and medical practitioners need to take that into account when evaluating whether children have ADHD.”
ADHD is the most commonly diagnosed behavioral disorder for kids in the United States, with at least 4.5 million diagnoses among children under age 18, according to the Centers for Disease Control and Prevention.
However, there are no neurological markers for ADHD (such as a blood test), and experts disagree on its prevalence, fueling intense public debate about whether ADHD is under-diagnosed or over-diagnosed, Elder said.
Using a sample of nearly 12,000 children, Elder examined the difference in ADHD diagnosis and medication rates between the youngest and oldest children in a grade. The data is from the Early Childhood Longitudinal Study Kindergarten Cohort, which is funded by the National Center for Education Statistics.
According to Elder’s study, the youngest kindergartners were 60 percent more likely to be diagnosed with ADHD than the oldest children in the same grade. Similarly, when that group of classmates reached the fifth and eighth grades, the youngest were more than twice as likely to be prescribed stimulants.