Almost one million kids misdiagnosed with ADHD

by Steve Ragan - Aug 19 2010, 07:00

According to new research by a Michigan State University economist, almost 1 million children in the United States are potentially misdiagnosed with attention deficit hyperactivity disorder (ADHD). What’s the reason for the misdiagnosis? They are the youngest – and most immature – in their kindergarten class.

Todd Elder, who authored the study, said that the youngest and most immature are more likely than their older classmates to be dosed with behavior-modifying stimulants such as Ritalin.

Fueled largely by increasing recognition of ADHD as a legitimate disorder within the medical community, prescriptions of psychostimulants to children diagnosed with ADHD rose by more than 700 percent in the U.S. between 1991 and 2005, Elder’s research shows.

According to the paper, in 2006, the Centers for Disease Control and Prevention estimated that 4.5 million children under age 18 were diagnosed with ADHD, with roughly 2.5 million of these children regularly using prescription medication to treat their symptoms.

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 results show the youngest kindergartners were 60-percent more likely to be diagnosed with ADHD than the oldest children in the same grade. Moreover, when that group of classmates reached the fifth and eighth grades, the youngest were more than twice as likely to be prescribed stimulants.

Overall, the study found that about 20-percent (900,000) of the 4.5 million children currently identified as having ADHD likely have been misdiagnosed. This wastes an estimated $320 million to $500 million a year on unnecessary medication, some $80 million-$90 million of it paid by Medicaid.

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.”

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.

The paper will be published in the Journal of Health Economics in conjunction with a related paper by researchers at North Carolina State University, Notre Dame, and the University of Minnesota that arrives at similar conclusions as the result of a separate study.

You can read it in full here.

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