The line between disease/disorder and "unsatisfactory performance" is drawn somewhat arbitrarily. But in general, those patients with an ADHD diagnosis have much more to gain from "stimulants" than those who do not have this diagnosis.
The potential for abuse of a drug should not limit its appropriate use, though this happens all the time. Also, the safety of ADHD medication is quite well understood, and even the long-term effects seem to be less than the disadvantages of the disorder itself. There may still be a lot of room for exact quantification, but at the moment it looks like ADHD medication is a "good deal" in general.
The potential for abuse of a drug should not limit its appropriate use, though this happens all the time. Also, the safety of ADHD medication is quite well understood, and even the long-term effects seem to be less than the disadvantages of the disorder itself. There may still be a lot of room for exact quantification, but at the moment it looks like ADHD medication is a "good deal" in general.