Caffeine as a Treatment
Some studies suggest that consuming lots of caffeine can improve focus, but there’s no evidence to suggest that caffeine affects hyperactivity or impulsivity. The amount of caffeine you’d need to consume to affect ADHD would probably cause agitation (not to mention spending too much time in the bathroom).
I don’t recommend drinking caffeinated beverages (or taking caffeine-containing pills) as a way to treat ADHD.