Attention Deficit Hyperactivity Disorder: Higher Risk for Early School Children

Children who enter school earlier are 30% more likely to be diagnosed with Attention Deficit Hyperactivity Disorder (ADHD). And this, even if their classmates are slightly older than them.

In France, depending on the date of birth of a child - and the date of the beginning of the school year - a child can take his first steps in school at two-and-a-half or three years. In the United States, it's the same thing. In some states, the registration deadline is set each year on 1 September.

Children born in August and enrolled in school are therefore among the youngest in their class. A new study, conducted by researchers at Harvard Medical School, reveals that they are more likely to be diagnosed with Attention Deficit Hyperactivity Disorder (ADHD). The results of this study are published in the New England Journal of Medicine.

More and more children under treatment

In the United States, the diagnosis rate of ADHD has increased dramatically in recent years. In 2016, more than 5% of American children were on treatment for this kind of disorder, against 3 to 5% in France. An increase due, according to the experts, to a greater recognition of the latter, to an increase in the incidence of the disease, or in some cases to misdiagnosis.

This is the case, according to the researchers in the study, for those children who enter school at a younger age. "Our results suggest the possibility that a large number of children are over-diagnosed and over-treated for ADHD because they are relatively immature compared to their older classmates at the beginning of primary school" explains Timothy Layton, lead author of the study.

30% more diagnoses

At two years of age, it is more difficult for a child to hold on and focus at three years. This can push teachers and parents to see a doctor. Because the three signs of ADHD are attention deficit, motor hyperactivity and impulsivity.

To carry out their study, the researchers focused on a large database. They compared the difference in diagnosis of attention deficit hyperactivity disorder according to the birth month of 407 000 children, born between 2007 and 2009 and followed until 2015. Thus, in the states that have September 1st as deadline for schooling, children born in August are 30% more likely to be diagnosed with ADHD than those born in September (and therefore attending school later). Researchers stress the importance of considering all the factors to consider before sending a child to a doctor.