It's also possible that social evolution has outstripped physical evolution and "pathologized" a condition that was previously desirable. For instance, in hunter/gatherer times having ADD may have been an asset for a hunter.
This is true and it is also true that in our society we tend towards creating pathologies in order to justify taking drugs that actually often have the same effect on most people. My baby sister was diagnosed with ADD but she found that marijuana worked better than the prescription. She got a 4.0 in college and graduated from a top law school and said that many of her fellow students had ADD and it was the hyper-concentration aspect of it that allowed them to do well with their intense studies. I think people should just be able to take drugs that help them out from time to time without having to be labeled with a pathological diagnosis.
"Tell me, what is it you plan to do with your one wild and precious life?" - Mary Oliver
