3/6/2012

Data from 937,943 children in British Columbia ages 6 to 12 between 1997 and 2008 showed that boys and girls born in December -- typically the youngest in their class, due to cut-off dates -- were 30% and 70% more likely to be diagnosed with attention-deficit/hyperactivity disorder than those born in January. Researchers also found that boys and girls born in December were 41% and 77% more likely, respectively, to be prescribed ADHD drugs that those born in January. The study appears in CMAJ.

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