I've never actually looked into it, I'm just going off of my personal experience and most other people that I know with ADHD.
Maybe we are all outliers, I've never looked into actual research studies for it, but I definitely have a similar effect drinking coffee or anything with caffeine versus taking medication, and most of the time when I ask someone else about it they will say that they've experienced similar cases. It's weird if science studies don't show the same though