I'd say over half the children with ADHD, do not have ADHD.
Discipline and challenge keeps the ADAHD diagnosis away. Schools and parent need to keep kids busy and challenged...
About 10 years ago, I knew several couples, who each had 10-11 year old boys.
Every one of those boys were on Ritalin.
One of the guys I work with was told his kid had to medicated to stay in school. They chose to home school him. He finished high school early and is now in college. Without drugs.