Results from two studies show that the youngest kids in a class are more likely to be diagnosed with ADHD than the oldest kids in their class.
The results of two studies, both scheduled for publication in the Journal of Health Economics, suggest that nearly 1 million children who have been diagnosed with ADHD might actually just young for their grade, adding evidence to support the idea of holding back children with Autumn birthdays (the cut-off in most states is September 1). The studies—led by researchers a Michigan State University (study 1) and multiple top universities (study 2), respectively—suggest that children who are the youngest in their kindergarten class are 60% more likely to receive an ADHD diagnosis than the oldest children in their class.
And the discrepancies don’t stop there; findings from study 1 show that the youngest among both fifth and eighth grade classes were more than twice as likely to use the ADHD drug Ritalin when compared with the oldest students in their classes. Although the agent certainly helps children with ADHD, it can cause unnecessary side effects—headaches, dizziness, and high blood pressure—in those who don’t truly have ADHD, according to study 2.
Todd Elder, Department of Economics, Michigan State University, and lead author of study 1, told USA Todaythat physicians should evaluate children for ADHD based on their age, not their grade, as there will always be kids in a given class who are a year older than others.
Noting the limitations of both studies, Elder cautioned that younger children may not be over-diagnosed with ADHD, as the study results would suggest. In fact, he said it’s possible that older children in a class might be under-diagnosed due to acting more maturely.