I remember seeing a study a few years ago that showed a lot of the negatives from Meth weren't inherent in the drug but from behaviors it encourages; like not sleeping.
I don't think I would say it "encourages" not sleeping. Rather it makes sleeping impossible. And that has bad effects. Drug causes something which causes something else, so you could say it is not the drug but its effects, but I would say that means it is the drug that causes it all. Don't take it if you don't want those "side-effects".