You make a good point, and I'm sure I could find some but mostly it's from living it and hearing of it. My grades have always been good so I've avoided medication, gladly enough. But my older brother was not so lucky, they gave him adderal. For him adderal was a way to focus and it shut off his personality. For the average person, adderal is speed and does the opposite, that's some proof. For myself, my experiences are mostly just observations that I then looked up because I was curious as to why I was "different" per say. I could drink soda before bed and still fall right to sleep when I was younger regardless of caffeine. As I've grown older I've learn to love coffee, and I realized that coffee chills me out and helps me to focus rather than stimulate me and make me hyper. I can drink a double shot of coffee and go straight to bed, hell, I'll drink one sometimes to help me sleep. It's strange, but I know I've looked up studies stating this, and that was after I realized the effects so I don't think the idea was put into my head and that's why I think it does that to me. I dunno, I'm not a genius, but it's my life and I definitely feel that I have reason enough to think I've got ADHD based off of the things I've read and effects I've observed.