Increased diagnosis of attention-deficit hyperactivity disorder despite stable hyperactive/inattentive behaviours: evidence from two birth cohorts of Australian children.

Diagnostic increases were not driven by rises in hyperactive/inattentive behaviours. A quarter of all children with an ADHD diagnosis recorded pre-diagnosis behaviours within the normal range. The increased likelihood of being diagnosed with ADHD for children from the later birth cohort was observed for children across the full range of ADHD-related behaviours.