Self-harm is a highly common behaviour in adolescents, which is associated with future attempted and completed suicide, and onset of mental illness.1 It is associated with significant distress (both as a cause and an outcome) and social impairment.2 It is therefore essential that we provide effective treatment. Self-harm is a hazardous behaviour that can occur in young people with any mental disorder, and indeed in young people with no psychiatric diagnosis.2 This demonstrates the need for specific treatments aimed at adolescent self-harm, which may confer additional benefits on top of treatments aimed at the underlying disorder. This is particularly true for young people who do need meet strict criteria for any psychiatric illness, but do have impairing self-harm.