The youngest children in a classroom are more likely to receive medication for ADHD than their relatively older classmates, a study from Finland confirms.

This ‘relative age effect’ likely occurs when the more immature behaviour of younger children is inappropriately treated as ADHD, the researchers say.

They analysed ADHD medication use among more than 7000 children born in 2005-07 following them until 2017 (to their 10th-12th birthdays depending on their year of birth).

Finnish children start first grade in the year of their seventh birthday. The cut-off date is 31 December, so the oldest children in the class are born in January and the youngest in December.