i used to dabble a bit in the business, but only when i had an overwhelming amount of work to get done at university, which usually was right around midterms and finals. i really didn't like the stuff- sure it made me focused, but it really fucked with me mentally and physically. things seemed real bleak on it, especially around november in montreal when the weather is grey, rainy, and cold. and for the rest of the week, i would be seriously depressed and have trouble sleeping. that may have been b/c i am already a fairly focused person and don't need the stuff though.