As someone who put in 70+ hours a week for 15 months straight without caffeine, and who is now doing 40 hours a week completely dependent on it, I can anecdotally disagree. It's all circumstanial. It's not forceful. It's a lack of discipline without the substance and knowing you're capabilities. My literally goal for the year is to remind myself how much more productive I was when I didn't live a life so dependant on caffeine, because I know it can be done because I lived it. Not comparing my life to yours. The bigger picture here is that anyone trying to achieve a higher state, should at least pursue a life where they stop introducing variables that have measurably been documented to ALTER bodily functions.