Skip to main content

You Say It’s Your Birthday…Squirrel!

Depending on her birthday, this little girl could be at increased risk of being (mis)diagnosed as having ADHD. Photo courtesy of ssdg4773.

Attention Deficit Hyperactivity Disorder (ADHD) is a serious matter. So it is worth paying attention when researchers find that many kids are apparently being misdiagnosed with ADHD because of their birthdays.

A study from NC State, Notre Dame and Minnesota finds that children who are born just before the cut-off date for kindergarten enrollment are 25 percent more likely to be diagnosed with ADHD than children born just after the cut-off date. In other words, the youngest kids in class are diagnosed with ADHD far more often than the oldest kids in class. The study is being published in a forthcoming issue of the Journal of Health Economics.

The researchers looked at kids born just before or just after the cut-off date because children born only a few days apart should have the same underlying risk of having ADHD. The significant disparity in diagnosis indicates that something is at play other than biological or medical factors.

The behaviors used to diagnose ADHD in kindergarteners are similar (or identical) to what is considered normal behavior in slightly younger children. So researchers believe that many of the younger kids in class are being misdiagnosed with ADHD because they are exhibiting age-appropriate behavior.

If birth date contributes to the misdiagnosis of even a small percentage of children, it could be a big deal – because so many kids are diagnosed each year. According to the CDC, in 2003 approximately 4.4 million children between the ages of 4 and 17 had been diagnosed with ADHD. It looks like some of those 4.4 million don’t have ADHD, but might be better diagnosed as being too young.