Self-harm often starts in pre-teens and teens and ranges from picking and scratching to wearing tight clothing or eating overly spicy food.

Teens who visited an emergency room for self-harm were more likely to return to hospital or even die than those who had visited for other reasons, a new study has found.

The study, published this week in the Canadian Journal of Psychiatry, also found the rates of visits by teens aged 13 to 17 for mental health problems rose 78 per cent during that time.