I have worked with a number of people that cut on themselves... From their prospective, it comes down to CONTROL. (ie) The cutting is a type of pain that they can control.. and for most, its a way of feeling in control or distracting from the untouchable or vague INTERNAL pain from past hurts, anger, pain, abuse, etc. (that pain..the internal pain, they can't control, cant make it stop and can't 'fix' it.. But the physical cutting is a type of pain that THEY INFLICT and can control the intensity of or the amount of pain... Plus it is much easier to focus on the expernal pain (of cutting) as a means of avoiding, distracting and feeling powerless over the internal pain. SOmething to think about