I was on Adderall (similar to Ritalin) for a while. The body begins to adjust though. My doc raised my dose once or twice and then I started using more than I should have. When I realised I was addicted and abusing it, I quit.

Now, months later, I've just asked my pdoc for another similar, but safer, option. She's prescribed slow-release dexedrine spansules. I have yet to get the rx filled, but I certainly hope it helps.