Kids born in August are diagnosed with ADHD more than kids born in September
A study compares kids in states with September 1 cutoff for kindergarten
Children who turn 5 just before starting kindergarten are much more likely to be diagnosed with attention-deficit/hyperactivity disorder than their oldest classmates. The finding bolsters concerns that the common neurodevelopmental disorder may be overdiagnosed.
“We think … it’s the relative age and the relative immaturity of the August-born children in any given class that increases the likelihood that they’re diagnosed as having ADHD,” says Anupam Jena, a physician and economist at Harvard Medical School.
Jena and his colleagues analyzed insurance claims data for more than 407,000 children born from 2007 through 2009. In states that require kids be 5 years old by September 1 to begin kindergarten, children born in August were 34 percent more likely to be diagnosed with ADHD than those born nearly a year earlier in September — just after the cutoff date. For August kids, 85.1 per 10,000 children were diagnosed with ADHD, compared with 63.6 per 10,000 for the September kids, the researchers report in the Nov. 29 New England Journal of Medicine.