i actually dont know and i didnt know any one who done it, i was just very very upset over something teenagerish and started to pick a scab on my arm, eventually i ended up with a huge patch of skin scratched away by my nails. It hurt and burnt but was strangely good.
Apparantly the endophenes released to cut the pain makes the person doing it feel good.. however it becomes addictable and as a teenager we get so upset over everything it becomes almost needed.

i dont know where it came from, and i dont know wot makes us even start to do it.. i understand the humilation and upset it all causes and that yes its odd but doenst make some one a freak so i am quite open about it as it can get very dangerous and teenagers have really caused damamge and even died , so as an adult i hold my hands up and say i did it and i managed to stop with help.

I imagine its gone on for years though, old as time as with the drugs and over doses.