I don't really understand why people do it. Not like "they're doing it because they are depressed and feel bad", I had depression myself but never had a call to injure myself. I hate pain, and doing something painful to myself while I'm already feeling bad doesn't really sound appealing. So I don't quite get what self-harm gives people so they keep doing it.
Like, is it a way to "ground" yourself and stop dissociating, or is it "just to feel anything at all", or as a "punishment", or something else?
For everyone it's different, for myself it started off as "I wonder what that would feel like". Obviously any mentally balanced person would never have that kind of thought occur, but it was curiosity that started it. Then I became more interested in the sensation and it almost started to become addictive.
So yes, I think the want to feel anything at all plays a big part for most people, and a lot do tend to find it addictive too.