I have to correct you here--ADHD stimulant meds like Ritalin do not have amphetamines in them. The chemical compound is called methylphenidate, and yes, it's a chemical cousin--but you have to remember that "cousin" is far enough away to make a big difference, like the difference between wine and wood alcohol or sodium chloride and potassium chloride. I have ADHD and take extended-release methylphenidate, and the effect it has on me is very much like drinking a cup of coffee every three or four hours, except that it doesn't make me physically jittery the way coffee would. Because I also have autism, it helps me with transitions--that is, stopping and starting activities, moving from one thing to another--because it gives me a little more control over what I'm focusing my attention on. It's a useful tool in my kit for coping with life in a neurotypical world.
Even someone abusing methylphenidate--like, for example, a college student taking it as a study enhancer while cramming for finals (that's the most common type of abuse where Ritalin is concerned)--would get an effect more similar to coffee than to methamphetamines. Methylphenidate also doesn't create tolerance or addiction--there are no withdrawal symptoms; in fact, I can stop taking it on the weekends if I like, or take it only on the days when I go to class. You could probably get psychologically addicted (the type of thing where you feel like you can't function without it even though you aren't physically addicted), but you can get psychologically addicted to




or gambling much the same way and they aren't chemicals at all.
I know it's off topic, but I really think it needs to be said because there are so many people out there with ADHD who are really struggling and who aren't living up to their potential, and who are scared of taking meds because they're afraid it will turn them into a drug addict. It can help--it can give you enough of an edge to start making progress. And it is NOT the same thing as doing meth.