I wasn't really referring to the side effects/withdrawals though - as far as testing is concerned, it's pretty much all about the performance enhancement! If it's having a negative effect on your performance, well that sounds like a personal problem to me!
Funny thing is, there's plenty of legal activities/substances that can have similar negative effects - stay out on the p*ss all night before a game, stay up all night shagging the missus (the neighbour, the cat, whoever) the night before a game, even eating a huge amount of junk food before the game.