I started DSH in Year 10 and continued right the way through A-Level and University and it remained my coping strategy when I started work.
I was very unhappy for a lot of reasons and never really got any treatment other than anti-depressants. My attempt at attending counselling was a complete disaster.
However, I took myself in hand, lost six stone, started running and other exercise and lots of other things started to fall into place.
I genuinely struggle to remember when I last harmed, certainly before I met DH, I think we're looking at 3-4 years now. I do worry now we're TTC that I may find things difficult again but I try to remain positive.
I've shared my story as I know my parents found it so difficult, and it seems to be a growing problem.
It can and does get better though - just be there for your DC, try not to be judgemental and remember it won't make sense to you, but it will to them. Treatment of whatever kind is difficult. If I'm honest I think marathon training is a displacement activity - but at least it's a healthy one 