Immaturity may lead to diagnosis of disorder
The youngest children in the classroom are significantly more likely to be diagnosed with attention-deficit/hyperactivity disorder (ADHD) - and prescribed medication - than their peers in the same grade, according to a study just published in CMAJ (Canadian Medical Association Journal).
ADHD, which is often treated with prescription medication, is the most commonly diagnosed behavioural disorder in children. Two recent studies have shown a link between the relative age of children and diagnosis of ADHD and prescription of medication. Younger children in the same grade as children who may be almost a year older may appear to be immature compared with their older peers. This apparent lag in maturity has been called the "relative-age effect" and influences both academic and athletic performance.
Researchers from the University of British Columbia were interested to see whether this relative age effect was present in Canada and looked at a large cohort of 937 943 children in British Columbia, a province where the cut-off for entry into kindergarten or grade one is Dec. 31. The research included children who were between 6 and 12 years at any point during the 11-year study conducted from Dec. 1, 1997 to Nov. 30, 2008.
Researchers found that children were 39% more likely to be diagnosed and 48% more likely to be treated with medication for ADHD if born in December compared to January. Due to the Dec. 31 cut-off birth date for entry into school in British Columbia, children born in December would typically be almost a year younger than their classmates born in January.
"The relative age of children is influencing whether they are diagnosed and treated for ADHD," said lead author Richard Morrow, University of British Columbia. "Our study suggests younger, less mature children are inappropriately being labelled and treated. It is important not to expose children to potential harms from unnecessary diagnosis and use of medications."