Adverse life experiences and triggers for self-harm in young people aged 12–26 years in inner south London: a retrospective observational study

Background The prevalence of self-harm among children and young people in the UK is increasing, with few accessing formal support. Drivers of self-harm remain poorly understood, and evidence-based opportunities to intervene are scarce. We aimed to identify factors associated with self-harm in young people to inform local action. Methods In this retrospective, observational study, we identified 196 residents of the south London Borough of Lambeth, aged 12–26 years, presenting to two emergency departments for injuries related to self-harm in the 2015–16 financial year (April 1, 2015, to March 31, 2016). A pragmatic sample size of 100 was selected via computer randomisation for further analysis. Electronic mental health records were retrospectively analysed using a data collection protocol that was validated with researchers before data collection. Demographics and psychiatric history were obtained from pre-coded databases linking electronic mental health records and Hospital Episode Statistics data on emergency department attendance for self-harm. Presentation details and social risk factors were derived from assessment of case notes pertaining to the 2 weeks after first presentation; we noted any risk factors that had been positively recorded. Data relating to the individual's first presentation within the study period were used; subsequent attendances were not included in the sample. We analysed the data using descriptive statistics. Ethical approval for data access and linkage was granted by the Oxford Research Ethics Committee C (18/SC/0372), Clinical Records Interactive Search system Oversight Committee (project numbers 14–026 and 19–004), and the National Health Service (NHS) Health Research Authority Confidentiality Advisory Group (reference ECC 3–04(f)/2011). This study received approval as an audit project through Southwark Operational Directorate in the South London and Maudsley Foundation NHS Trust. Findings 48 (48%) of the 100 selected participants had documented experience of psychological trauma, including exposure to violence. 18 (18%) lived in unstable accommodation, and 20 (20%) were known to social services. Difficulties at home (16 [16%]) and stress relating to housing, school, or financial pressures (13 [13%]) were common documented triggers for the self-harm episode at presentation. Peer influence was rarely noted, although 27 (27%) had recorded experience of bullying. Interpretation Adverse life experiences were prevalent and align with wider population prevalence estimates. Common triggers for self-harm relate to home and school environment and wider socioeconomic stressors, supporting the link between wider determinants of health and self-harm, and contributing to the case for public health action. Risk factors and triggers identified provide potential areas for additional targeted support to prevent development or escalation of self-harm behaviours. Funding UK National Institute for Health Research Biomedical Research Centre at South London and Maudsley NHS Foundation Trust, and King's College London.