Self-harm in children and adolescents by ethnic group: an observational cohort study from the Multicentre Study of Self-Harm in England

Background
Studies report an increasing incidence of self-harm in children and adolescents, but the extent to which this is seen in different ethnic groups is unclear. We aimed to investigate rates of emergency department presentations for self-harm in children and adolescents by ethnicity, as well as to examine their demographic characteristics, clinical characteristics, and outcomes.

Methods
In this observational cohort study, we used data on hospital emergency department presentations for self-harm in children and adolescents aged 10–19 years between 2000 and 2016 from the Multicentre Study of Self-harm in England. This study collects data from five general hospitals in Manchester, Oxford, and Derby in the UK, and defines self-harm as any act of intentional self-injury or self-poisoning, regardless of intent. All children and adolescents aged 10–19 years for whom ethnicity data were available were included. Mortality follow-up was available through linkage with mortality records from the Office for National Statistics. Rates of self-harm over time, demographic and clinical characteristics, and self-harm methods were investigated by ethnic group. Risk of repeat self-harm and mortality following an initial presentation for self-harm was compared by ethnic group using Kaplan-Meier curves and Cox proportional hazards models.

Findings
Of 14 894 individuals who presented at hospitals with self-harm, 11 906 had data for ethnicity, of whom 10 211 (85·8%) were White, 344 (2·9%) were Black, 619 (5·2%) were South Asian, and 732 (6·1%) were other non-White. Rates of self-harm were highest in White children and adolescents but increased between 2009 and 2016 in all ethnicities. Mean annual rates of self-harm per 100 000 population were 574 for White, 225 for Black, 260 for South Asian, and 344 for other non-White groups. Increases in rates of self-harm between 2009 and 2016 appeared slightly greater in Black groups (incidence rate ratio 1·07 [95% CI 1·03–1·11]), South Asian groups (1·05 [1·01–1·09]), and other non-White groups (1·11 [1·06–1·16]) than in White groups (1·02 [1·00–1·03]). Children and adolescents from a minority ethnic background were more likely to live in areas of high deprivation and were less likely to receive a specialist psychosocial assessment than were White children and adolescents. Children and adolescents from minority ethnic groups were also less likely to repeat self-harm. However, there were no differences in suicide mortality by ethnic group, although the numbers were small.

Interpretation
Minority ethnic children and adolescents accounted for an increased proportion of self-harm presentations to hospital over time compared with White ethnic groups. The minority ethnic groups also tended to be more socioeconomically disadvantaged and were less likely to receive a psychosocial assessment. Socioeconomic disparities need to be addressed, and equitable access to culturally sensitive comprehensive psychosocial assessments must be ensured.

Funding
UK Department of Health and Social Care.