Ronin: The body can become addicted to it, like pretty much any drug. Pain releases endorphins, the happy-making things in your brain. I'm not too sure about some drugs, but I do know that alot make the brain release this exact chemical. Of course, drugs usually have many other side effects also. Cutting just releases endorphins. And I'm guessing it's more convienient than drugs. Can't be fined/jailed for it and all. I know people that have started cutting as part of the 'emo trend' and then quite literally gotten addicted to it and been unable to stop. It's always hard to stop.