Attention-deficit/hyperactivity disorder, typically referred to as ADHD, is one of the most common learning disabilities. According to the Center for Disease Control and Prevention, approximately 9.4% of children 2-17 years of age in America have been diagnosed with ADHD at some point.

A new study published by The New England Journal of Medicine suggests that school cutoff dates may affect ADHD diagnosis.

Grade cutoff dates in most states are on or around September 1, which allows students close to this date to be in the same grade yet nearly a year apart in age. The characteristics of ADHD, which include hyperactivity, fidgeting, impulsivity, forgetfulness and attention difficulty, are present to some extent in most young children, and usually become less apparent with age. Because children in the same grade can be almost a year apart, those who are younger and thus more likely to be “rowdy” have a greater chance of being diagnosed with ADHD than their older counterparts.


The research study, performed by a team led by Timothy Layton, PhD from Harvard Medical School, used data from states in which the school cutoff date was September 1. Kindergarten entry dates were looked at to obtain the results. The team found that 85.1 per 10,000 children born in August were diagnosed with ADHD, compared to the 63.3 per 10,000 children born in September.

The increased likelihood of ADHD diagnosis among those born in August can be both harmful and helpful. ADHD medications can have adverse effects, which can be a concern for parents, teachers and physicians. If younger children are being misdiagnosed and placed on medication because they’re being compared with their older, more mature classmates, they could suffer from side-effects including sleep problems, headaches, irritability and nausea for virtually no reason.

On the other hand, younger children of a certain grade may benefit from extra help in order to compensate for academic struggles that may result from their age relative to their peers. Evidence shows that younger children in a school cohort do not perform as well as older children, attend college less frequently, and engage in juvenile criminal behavior more often.

Whether a potential misdiagnosis of ADHD is more harmful or helpful is both a matter of opinion and dependent on the situation. What matters about this study is that it is raising awareness of the disorder as well as differences among children in the classroom, which can further assist educators in specialized teaching.

Photos: Bainum Family Foundation

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