October 29, 2010
Two studies published recently suggest there could be something wrong with the way ADHD is diagnosed in young children in the US, one found that nearly 1 million kids are potentially misdiagnosed just because they are the youngest in their kindergarten year, with the youngest in class twice as likely to be on stimulant medication, while the other study confirmed that whether children were born just before or just after the kindergarten cutoff date significantly affected their chances of being diagnosed with ADHD.
Papers on both studies by US researchers are in press, to be published in the Journal of Health Economics, the first being a corrected proof that was first available online in June, and the other appeared online on 4 August.
In the first paper, Dr Todd Elder, assistant professor of economics at Michigan State University, looked at a sample of nearly 12,000 children from the Early Childhood Longitudinal Study Kindergarten Cohort, which is funded by the National Center for Education Statistics. He analysed the difference in ADHD diagnosis and medication rates between the youngest and the oldest children in a kindergarten grade.
- A d v e r t i s e m e n t
He found that the youngest children were significantly more likely to be diagnosed with ADHD and to be prescribed behavior-modifying stimulants such as Ritalin than their older classmates. He told the press that the “smoking gun” was that the diagnoses depended on the children’s age relative to classmates and the teacher’s perceptions of whether they had 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.”
“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,” he urged.
Elder said medicating such children inappropriately was a cause for concern not just because of the effect of long term stimulant use on their health but also because it costs a lot of money: he estimated about 320 to 500 million US dollars is being wasted on unnecessary medication of young children for ADHD, of which 80 to 90 million is funded by Medicaid.
From his analysis, Elder found that the youngest kindergarten kids were 60 per cent more likely to be diagnosed with ADHD than the oldest in the same grade, and also, by the time those groups reached the fifth and eighth grades, the youngest were more than twice as likely to be on prescription stimulants.
Elder estimated that overall in the US, the misdiagnosis rate is about 1 in 5, that is around 900,000 of the 4.5 million children currently diagnosed with ADHD have been misdiagnosed.