If you have found this blog, you have probably read the recent report from a large study out of the Michigan State Univ of young children being overdiagnosed with ADHD. From a data set of 12,000 children, the authored discovered that children who were the youngest in class had a higher likely of being diagnosed with ADHD, possibly inaccurately. To read futher on the public annoucement, go to https://abcnews.go.com/Health/Wellness/adhd-misdiagnoses-identified-study/story?id=11418898

So, what to make of this. First, the study has not been published yet so there is no way to assess the method of data collection. Why is this important? Because the conclusions of a study are strongly influenced by the way data has been collected and analyzed. Remember the expression “Garbage in, garbage out”? The quality of data is critical to the validity of the interpretation and conclusions. This comment in no way impeaches the study, it just adds a greater awareness of how to evaluate scientific conclusions.

It is important to keep in mind that the diagnostic criteria for ADHD goes beyond just having symptoms. In addition to symptoms (hyperactivity much more likely to be observed than inattention), symptoms have to cause impairment. Keeping this in mind, one can see how children can be overdiagnosed when all the diagnostic weight is placed solely on observed symptoms. In addition, although there is greater reliability (agreement among observers) for hyperactivity, there is less reliability for inattention. Therefore, such observations are subject to misidentification leading to misdiagnosis.

And lastly, symptoms have to be developmentally inappropriate for diagnostic inclusion. This is critical. So, comparing behaviour of a 5 year old to a 6 year is not the measure of clinically relevant symptoms. Since development occurs quickly over the years of childhood, behavior has to be compared to same age children. In this study, there seems to be the bias of observers who are comparing two different age groups leading to erroneous conclusions.

Lastly, the accuracy of the diagnosis is improved if a first degree family member has been diagnosed or seems to have convincing symptoms of ADHD. Remember, 75% of the cause for ADHD is genetic. If a parent has ADHD, it is very likely that the symptoms of the child, if developmentally inappropriate, strongly support this diagnostic conclusion. Was this part of the diagnostic process for this study? Well, we don’t know yet because the study hasn’t been published. We will have to wait and see.

Hopefully, after reading this blog you are now more aware of the complexity of scientific research and it’s conclusions. At the very least, you are now less likely to accept the blanket conclusion of press stories.

Again, thank you for your interest. David W. Goodman, M.D.