My undergrad gen-ed requirements included a theory of learning class. I took it around 2008. For my semester presentation, I did a review of ADHD research. The

My undergrad gen-ed requirements included a theory of learning class. I took it around 2008. For my semester presentation, I did a review of ADHD research. The various articles I read said the percentage of the population (in the US) with ADHD was between 4% and 8%, but my relatives, who are school teachers, said at the time that 80-90% of their students were being treated for ADHD.