The National Institute for Health and Care Excellence (NICE) has defined self-harming behaviour as:

Self-harm can be divided into two broad types: self-injury and selfpoisoning. The definition of self-harm is therefore purely behavioural and it includes a spectrum of risk-taking behaviours (Box 19.1). This spectrum includes smoking, tattooing, recreational alcohol and drug misuse, food restriction and promiscuity. Motivation must be appraised separately. Suicidal intent is associated with self-harming behaviour, particularly with self-poisoning, but the behaviour does not in itself predict underlying intent. Suicidal intent must be assessed specifically (see Risk assessment).

This chapter focuses on self-harming behaviours in 12- to 18-year-olds presenting to professionals working in child and adolescent mental health services (CAMHS), from single acts of self-harm posing little medical risk to multiple acts posing serious risk to life. Young people who self-harm form a highly heterogeneous population.

Self-harming behaviour has been the focus of scrutiny from public health, service provision, professional/therapeutic and patient/carer perspectives over the past decade or so. Although awareness of self-harm has increased, little progress has been made in its evidence-based management by professionals (Hawton et al, 2009).

The NICE guideline on longer-term management of self-harm was published in 2012 (National Institute for Health and Clinical Excellence, 2012). This covers young people aged 8 years and over and focuses on the longer-term management (after the first 48 hours) of both single and recurrent episodes of self-harm. The guideline is both an update and a continuation of the 2004 guideline on short-term management (National Institute for Health and Clinical Excellence, 2004), and it informs this chapter.