It is way over diagnosed, especially in the US. One of the issues is a lot of the diagnosis is taking place when a child is really young where there are many other factors in their life that can contribute to exhibiting some of the symptoms of ADHD/ADD. Also, there are a lot of other mental disorders that have many parallels with ADD/ADHD, resulting in a wrong diagnosis. This happens all the time and is why a lot of children or adolescents are on amphetamines, methylphenidate, strattera, lisdexamfetamine, SSRI's, SNRI's, etc. A lot of the children need a different approach and a different diagnosis. Also the education system in America is poorly run, creating "problem kids" who, they start to classify as ADD/ADHD, who really they need a different learning enviroment, as well as a different rewards/consequences system.
You see today that there is a large percentage of male students of all ages performing poorly in school, getting constantly in trouble, being classified as...