Breadcrumb Home Study finds more children diagnosed with ADHD than expected Wednesday, September 5, 2018 https://www.cnbc.com/2018/08/31/adhd-diagnosed-in-about-10-percent-of-us-childr… A study from the UI College of Public Health has found that the number of children diagnosed with ADHD has increased significantly in the last 20 years, to 10.1 percent.