If you want one that sneaks up on you, try fen-phen. No noticeable side effects and then you die of a heart attack.
As for modafinil, a quick look doesn't turn up any long-term safety studies (pub med is either down or even slower than usual today, which amounts to the same thing, so I might be missing something), except for one 9-week study. You could smoke for 9 weeks without being affected much.
It's not like it's a rare thing for drugs to turn out to be harmful. We'll just have to wait and see.
EDIT: given the lack of long-term safety studies, but also the lack of problems with short-term studies, I personally would use modafinil for finals week or a long car trip or something like that but not day-in day-out for years.
As for modafinil, a quick look doesn't turn up any long-term safety studies (pub med is either down or even slower than usual today, which amounts to the same thing, so I might be missing something), except for one 9-week study. You could smoke for 9 weeks without being affected much.
It's not like it's a rare thing for drugs to turn out to be harmful. We'll just have to wait and see.
EDIT: given the lack of long-term safety studies, but also the lack of problems with short-term studies, I personally would use modafinil for finals week or a long car trip or something like that but not day-in day-out for years.