So...who REALLY has ADHD?

In light of a recent conversation in class, curiosity has been spiked on the topic of who has ADHD and who does not. It is not at all uncommon or rare to encounter a student today that is medicated for attention deficit symptoms. That fact alone raises the question of, does everyone that is diagnosed with ADHD actually have it?
Scientists have recently found genetic evidence for ADHD. Although characterized by differences in behavior and a lack of an adequate attention span, there is now evidence that children with ADHD are more likely to have DNA mutations than children without ADHD; in other words, they are more likely to have DNA duplications or missing DNA segments.
This finding is extremely significant in that it can provide a purely scientific backing to diagnoses of ADHD. In the case of a dispute or uncertainty, a test can be run that can compare the DNA of a possible ADHD child to one without ADHD. Interestingly, these differences in DNA are similar to the DNA mutations found in people with schizophrenia and autism.
A child's environment and raising is not yet being completely ignored as a possible contributor to the development of ADHD, but at least now genetics can be shown to play a part. This can help provide a much clearer, surer diagnosis.

Sources: http://www.sciencedaily.com/releases/2010/09/100929191312.htm