ADHD patients were three years behind. This quantifies the evidence from physical activity data. Activity peaks in infancy. Dopamine neurons decrease over time. Thus a three year old is more active than a twelve year old. The latter is more active than a twenty year old, than a 40, than an 80 year old. Thus the trajectory of decrease of activity level is shifted to the right in children with ADHD. This study implies the 10 year old with ADHD may move as much as a seven year old.
It would be useful to correlate these brain immaturities with actual movement rates.