ADHD in the News: BC study finds “December babies” (especially girls) more likely to be diagnosed & treated

As reported first in Monday’s national news, a newly released UBC study headed by Robert Morrow has uncovered some interesting observations about the diagnosis and treatment of childhood ADHD.  Nearly 940,000 children aged 6 to 12 were studied.

A main conclusion is that children born in December might, due to immaturity, be at higher risk of misdiagnosis.  As you may have already heard, “December babies” were 39% more likely to be diagnosed and 48% more likely to receive treatment.  This was even more pronounced for girls, who were 70% more likely to be diagnosed than their January counterparts in the same grade.  The study included a massive number of BC schoolchildren aged 6 to 12 – nearly 940,000 of them.

At least for boys, the rates of diagnosis (close to 7%, varies slightly by month of birth) are in line with the DSM-IV (the big book of labels physicians, psychiatrists, and psychologists use to define different conditions).  Girls have always been harder to pin down as far as ADHD goes.  They often present as “social butterflies” and aren’t usually as disruptive as boys.  Their rate of diagnosis in the study hovers around 2%.  The now-infamous “December babies” are diagnosed at 7.4% for boys (1.7% more than their January counterparts) and 2.7% for girls (1.1% more than their January counterparts).

Per 100 children, this means only 2 more boys & only 1 more girl.

If I may talk statistics for a bit here (oh! horror!  Bear with me – I’ll make it worth your while!), with a sample of nearly a million children, this is a “significant” effect.  In stats-speak, all that means is that there is a reliably big gap between groups.  So, even though we are talking about 3 extra kids out of 100, when you multiply that by nearly 1 million, it doesn’t mean “holy cow, look at all the kids,” it means “the number-crunching is sound – there is a reliable difference between January & December rates.”  Basically, any time you measure 1 million of anything, you are bound to find “statistically significant differences” because number-crunching loves lots of data.  (See, was that so bad?)

As far as our December babies go, this could mean two other things: boys are under-treated and girls might be under-diagnosed.

So, in this group of children, girls with a diagnosis were much more likely to receive relief from their symptoms (about 0.6 percent were deprived of treatment).  1.4% of boys, on the other hand, were deprived of treatment.

Other estimates of prevalence (how often we find a certain condition) are closer to 4% for girls.  Thus, we might be missing more of them.  Girls with carefully diagnosed ADHD are at higher risk for mood and anxiety disorders, anti-social behaviour, substance abuse, and eating disorders.  That they are not receiving relief for their ADHD symptoms may worsen the problem.

What to do?

1. As always, careful assessment is key.  If you want to try intervention, see your physician.  If you want to know the truth, see a psychologist.  Many other things can masquerade as ADHD: depression, the effects of mistreatment, verbal memory problems, learning disability, boredom, and more.  Because ADHD is so widely known, people, teachers, and parents might be quick to jump to this conclusion (just yesterday, I diagnosed a boy with Asperger’s – his mother’s first suspicion was that he might be ADHD).  Children with a bona fide diagnosis of ADHD are also very likely to have another difficulty (the most likely being learning disabilities or oppositional behaviour).  As mentioned in a previous post (ADHD or LD?), a poor verbal memory can come across to others as lack of attention.  That the problem is present across settings is one very pertinent observation.

2. I would argue that the “stigma” of ADHD is lessening.  Kids are used to it; it’s the grown-ups that seem to worry more about it.  What’s worse, in my opinion, is the stigma surrounding medication.  Much of the scare-mongering is downright false.  It is not an easy “cop out” solution & it won’t fix misbehaviour.  But depriving a child of effective treatment for ADHD heightens their risk for school drop-out, street drug use, poor academic and vocational outcomes, and feeling like a failure.  There are some ways to manage the child’s environment but the time and effort poured into these just don’t translate into improvement in the kids’ outcomes.

It is clear that many children are over-diagnosed with ADHD & receive medication they don’t need.  This is certainly something we need to fix.  However, at the same time, the under-diagnosis and failure to treat other kids who really do have ADHD is just as tragic.

To sum up, the December babies’ rate of diagnosis is closer to what we think the true rates of ADHD are.  Are they being over-diagnosed or better detected?  Girls – they are more likely to receive treatment for their condition – maybe they are the lucky ones?

Do let me know what you think.

The original news release from UBC:

The original academic paper in the Canadian Medical Association Journal:;cmaj.111619v1


About tanya.spencer

Dr. Spencer has worked with families, schools, and residential treatment settings using an evidence-based framework and cognitive-behavioural perspective. She specializes in learning problems, attachment, mood disorders, teen self-harm and the autism and fetal alcohol spectra.
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One Response to ADHD in the News: BC study finds “December babies” (especially girls) more likely to be diagnosed & treated

  1. Arlette says:

    Your extrapolations and possibilities sound logical to me. The stats lesson and myth-busting are refreshing.

Leave a Reply to Arlette Cancel reply