I think of it less as being dependent on a substance and more as being able to cleanly segment my life. Especially with something like Adderall XR which has a 6-8 hour duration, it is pretty straightforward to turn on and off. Then on days off or after work it is easier to feel no particular obligation to do anything work related. Another bonus is getting so much done when 'on' that your time off is free from any anxiety around work achievements.

That said I had a similar relationship to caffeine, it was more intense than adderall/ritalin to me but the afternoon drop off and affects on sleep/mood were too much and I have cut way back.