Natural tolerance to certain stims?

[pankreeas]

Swim has tried various prescription and non prescription stimulants recreationally, and only a select few really produce much effect, like coke. Minimal effects from adderal and virtually nothing seems to come from using methylphenidate up to 50mg, which nearly all people get nice effects from, while swim falls asleep.. Swim just consumed 50 mg again as a final test with an empty stomach and no other substances, 30 min in and drowsiness is setting in bigtime.. wuh is wrong with swim?? And btw since almost no effects are gotten from these.. then should swim pretty much just throw out his benzedrex inhalers, since he remembers hearing they are pretty much the equiv of a 1/5 dose of adderal? and adderal having almost no effect on swim..

*Edit* ok 2 hours have passed since swim ingested the 50mg methylphenidate and thankfully the oncoming sleepiness changed to alertness. Still not even a hint of euphoria to speak of... oh well least swim didn't fall asleep this time. In all swim would equate it with poppin some caffeine pills.