The youngest children in a class have been found to be more likely to be diagnosed as having ADHD, possibly due to their being developmentally behind their older classmates.
Watoto wachanga zaidi darasani wamegunduliwa kuwa na uwezekano zaidi wa kugunduliwa kuwa na ADHD, labda kwa sababu ya ukuaji wao nyuma ya wanafunzi wenzao wakubwa.