Another thing I only very briefly touched on is that just because someone is taking ritalin or a similar medication doesn't mean they actually have ADD or ADHD. They've gone to a shrink with particular issues and the ritalin is prescribed to help with that. Some people get through the day by drinking five mocha frappa caramel latte chinos or some other hypercaffeinated beverage, some people take ritalin. These are normal adults who aren't in school and don't have parents in charge of them to disobey.
It's true that traditionally people associate ritalin and aderal with being a pacifier for the annoying kid who won't shut up, do his school work and listen to mom and dad. But there are a bunch of other people who may not necessarily be ADD/ADHD and get some benefit from it.
Hell, I know I've spent more than one late night doing homework wired out on a bunch of Red Bull and it helps me to focus on the task at hand (plus stay awake). I know I'm not ADHD but the general class of stimulants helps me concentrate in particular situations.