Mental Health

Can a Child’s Birthday Predict ADHD?

Can a Child’s Birthday Predict ADHD?

 
Hello. My name is Dr. Robert Findling. I am the director of the Division of Child and Adolescent Psychiatry at the University Hospital Case Medical Center and I am a Professor of Psychiatry in Pediatrics at Case Western Reserve University.

Today in this posting, I’ll be talking about 2 articles that consider the same topic: the relationship between a child’s birthday, and the incidence with which they are diagnosed and treated for ADHD [attention deficit hyperactivity disorder]. These 2 articles were published in September’s issue of the Journal of Health Economics.

Can a Child’s Birthday Predict ADHD?

Robert L. Findling, MD

10/08/2010 – Hello. My name is Dr. Robert Findling. I am the director of the Division of Child and Adolescent Psychiatry at the University Hospital Case Medical Center and I am a Professor of Psychiatry in Pediatrics at Case Western Reserve University.

Today in this posting, I’ll be talking about 2 articles that consider the same topic: the relationship between a child’s birthday, and the incidence with which they are diagnosed and treated for ADHD [attention deficit hyperactivity disorder]. These 2 articles were published in September’s issue of the Journal of Health Economics.

The lead author on the first article is Evans, and the lead author on the other article is Elder. These authors examine the question of whether children who were relatively younger than their classmates were more likely to get a diagnosis of ADHD or receive medical treatment for this condition.

To address older vs younger children, the authors used data from large data sets. The authors examined youngsters whose birthdays were just before the school cut-off date for starting kindergarten. These were the relativity younger children. These younger children were compared with children whose birthdays were after the cut-off date, and this was the relatively older group. So you have 2 groups of kids — a relatively younger group putatively and a relatively older group putatively.

In both of these articles, the information came from 4 data sets, and the results were actually consistent across all 4 data sets. Children who were putatively younger than their classmates were more likely to receive a diagnosis of ADHD. Similarly, they were also more likely to receive medication treatment for ADHD.

For example in the article by Elder and colleagues, 8.4% of the youngsters who had birthdays before the kindergarten cut-off were diagnosed with ADHD. This is in comparison to 5.1% of the comparison group. Because these results are based on large data sets and not necessarily on direct clinical data, it would be interesting to confirm whether these findings could be replicated using a different methodology.

Certainly in the absence of clinical or developmental data, it would be useful to see: what are the determinants of this observation, and should it be further replicated? For example, how much of this result is driven by teachers’ concerns that are raised to families? Another possibility is what influence, if any, does holding back younger children who might not be seen as kindergarten-ready by their parents have on these results?

Regardless of the methodologic limitations and the unanswered questions, these articles really do raise important issues. Are we expecting too much from younger children within a kindergarten setting? Is there a divergence between maturity and educational expectations leading to symptoms that might be misperceived as ADHD? Certainly a careful and thoughtful assessment is necessary when evaluating a child in whom a diagnosis of ADHD is being considered, and part of the evaluation process should focus on whether the expectations on that child are in fact developmentally appropriate.

Certainly these articles raise important issues but also remind us that many syndromal but also nonpathologic states can mimic symptoms of ADHD. When evaluating a child for ADHD, whether the expectations being placed on that child are actually developmentally appropriate needs to be considered.

Although common, ADHD is still associated with diagnostic challenges and we should never forget that and certainly these studies bring attention to that fact. .

References

  1. Elder TE. The importance of relative standards in ADHD diagnoses: evidence based on exact birth days. J Health Econ. 2010;29:641-656. Abstract
  2. Evans WN, Morrill MS, Parente ST. Measuring inappropriate medical diagnosis and treatment in survey data: the case of ADHD among school-age children. J Health Econ. 2010;29:657-673. Abstract

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