Self harm is a topic which is now being mentioned more often, but is often mentioned in a similar way to leprosy. There seems to be mostly pity for anyone who practices self-harm, rather than sympathy. It often seems that there is more actual sympathy for addicts, or people with eating disorders. These do all have similarities, which is why I mention them together.
All of these are coping mechanisms, addictions, self-harm, eating disorders, all usually begin as methods to deal with stress or misery. My own started around the time of my seperation from my wife, a particularly stressful time as I also could not find a job, and was for a short time homeless before I could face asking my parents to let me move back in. I managed to avoid starting smoking, which came much later, and avoid any other substance addictions. After all affording them was a little difficult.
What I did find though, which did help me cope, was that I could hurt myself. The insides of my forearms are heavily scarred, some of these scars are from other events but many are my own doing. I was extremely careful at the time, not wanting to risk causing any serious damage to myself, so I made sure to sterilise any blade I used, make sure it was sharp and smooth, and so on. Pretty much in the same way that a heroin addict might sterilise a needle.
As to what exactly it did, that is hard to say. In a physiological context I could point out that pain and injury releases adrenaline and endorphins, a very definite rush. In a psychological context it is a control method. The pain and injury, and the scars or wounds left behind, are signs that there is still some little bit of your own life that you are the one in control of. I will admit that this is not sensible in any way but that does not stop it from being at least partly true. It is an addiction, and it does help to cope, but as with any addiction once the need for the coping mechanism is gone the habit often remains.
I finally stopped at the same moment as I decided to stop cutting my hair. Part of the reason I am so concerned about people cutting my hair is because of this, it represents the fact that I have decided that part of my life is over. I had a lot of help before stopping, but when I actually did it was something I chose to do on my own.
For anyone else who may self-harm, remember that as with any coping mechanism or addiction you need to be careful not to put yourself at serious risk. And I do recommend getting real help, whether from a professional or someone else. There are all sorts of ways you can try and cut down on the addiction, such as wrapping rubber bands around your wrists.
The big problem now though is the fashion self-harmers. A large part of the reason I have an intense dislike of emos is the impression they seem to be insistent on giving that self-harming somehow is required to be in their clique. Accept someone who does it, without showing revulsion, yes, but actively encouraging people to cut themselves is just twisted, and not in a good way.
Now to emphasize my view. I will not condemn anyone who does it any more than I would a smoker, or alcoholic, how they deal with it and how it affects others is what will tip the balance. Better than any of these methods is to get real help to deal with things, or to just deal with it alone, and no addiction should ever be taken up whether as a coping mechanism or anything else.