Can't speak to Vyvance, Adderall however has no ill side effects if you stop taking it. It allows your mind to move slower so stupid people can tolerate your 'awesomeness'. The only quasi addictive form of Adderall is 'instant' which any person prescribing it should be arrested for dealing narcotics. You can take too much, this gives you massive headaches but taking to little shouldn't have any side effects since it wears off every 12 hours anyways.