I'm not sure if thats so with caffeine, but i know when it comes to amphetamines that is true. that's why aderal is prescribed to patients with adhd to calm them down. i don't have any sort of add, and i took a 60mg aderal and i was up for 2 nights, whereas my friend with adhd can barely sleep if he doesn't take em. i don't know if the same goes with caffeine, but they are both stimulants. try something stimulant free, i believe there is a stimulant free version of ragnarok which i hear works pretty well.