You're conflating "not medicating" with "not treating", which is exactly the sort of thing that feeds the criticism that U.S. overdiagnosis rates are being driven by the pharmaceutical industry. Behavioral therapy is also effective, and avoids some of the negative impacts of medication. There are studies that compare medicated ADHD patients to untreated ADHD patients over the course of adolescence; but people who are skeptical over the over-prescription of ADHD drugs aren't actually advocating for non-treatment and non-intervention. Almost no one doubts that ADHD is a real problem for some children that requires medication. The question really is about the extent of overdiagnosis in the US, and the long-term use of medication for children, especially very young children. Stimulant drugs are not recommended for children under 6, and yet still something like 1% of US children under 6 are taking them. Both ADHD diagnoses and pharmaceutical treatment is far, far more prevalent in the US than other developed countries, and it is certainly a good question as to why. Parents naturally have a lot of anxiety about their children's schooling, and the marketing of ADHD plays upon and exacerbates that anxiety (to the extent that if you mention any hiccups in your child's adjustment to school, people immediately begin talking about ADHD). It is also true that kindergarten is the new first grade in terms of literacy expectations, which means more long, boring desk work for young children who are frequently seeing their exercise time reduced or eliminated. Those are problems also.