I'm a late ADHD diagnosis (37 now, diagnosed 35) and one thing I noticed is that I needed way less than they would prescribed. I was given 2 15mg tablets a day, and I would take 1/4 of one once in a morning, maybe twice a week. It has been life changing, for days when I need to work through a to-do list rather than something intrinsically motivating. But if I had continued with the prescribed does, I would have stopped—since it had so many side effects.