Self-harm is of public health concern not only because of the immediate physical harm that it causes, but also due to its association with psychological distress, and elevated risk of suicide [1,2]. It is rare under the age of twelve, but its incidence increases rapidly throughout the early teenage years, particularly among girls [3]. Most episodes do not come to the attention of healthcare services - in a recent UK sample, only one in eight 15–16 year olds received medical attention the last time they self-harmed [4] - therefore community-based studies are needed when estimating prevalence among teenagers. The largest such study in England to date - a self-report survey conducted in 41 schools - reported a lifetime prevalence of 13.2% among 15–16 year olds in 2000/2001 [4]. A more recent study in Sweden reported a lifetime prevalence of 17.1% among 17 year olds [5].
