The youngest children in a class have been found to be more likely to be diagnosed as having ADHD, possibly due to them being developmentally behind their older classmates. They also appear to use ADHD medications at nearly twice the rate of their peers.

In some cases, an inappropriate diagnosis of ADHD may reflect a dysfunctional family or a poor educational system, rather than any true presence of ADHD in the individual. In other cases, it may be explained by increasing academic expectations, with a diagnosis being a method for parents in some countries to get extra financial and educational support for their child. Behaviours typical of ADHD occur more commonly in children who have experienced violence and emotional abuse.