I'm sure mild doses improve productivity for most people, but I would bet their behavior would turn manic at a lower threshold than people in the ADHD spectrum.

Living with ADHD is extremely frustrating. Without medication there were many days where I'd go to work, get side-tracked for a moment, and accomplish absolutely nothing. Operating that way in college is fine, since you can usually find time to cram, but in the real world every day is finals day.

I also tend to engage in lots of negative novelty-seeking behavior: cheating on girlfriends, speeding since I can hardly pay attention to the road at 55, drinking too much, etc. I'm vaguely anhedonic and insatiable, which has led to great success in my career, but I never enjoy it much.