Sophie was a nice Christian teenager, the much loved daughter of decent hard-working parents. One night she came back from babysitting and, almost without conscious motive, hit her leg with a coathanger. Then she tried whipping herself with a belt. The following day she scratched her arm repeatedly with the point of a compass. The sensation produced a warm sense of wellbeing, a release of tension.

Thus began an eight year struggle to conceal what was happening from her parents and friends; to reconcile this addiction with her faith; to find a stronger sense of self-worth; to find healing. Slowly, with lapses, she learned to identify the triggers - and to realise that Jesus does not reject the self-harmer.

Today Sophie works with teenagers - one teenage girl in 10, and one teenage boy in 25, struggles with self-harm - and offers considerable insight into how this very common problem can be tackled.