# Self-harm incidence among children and young people 2019–2023: time series analysis of electronic health records in Greater Manchester, England

## TL;DR

This study analyzed self-harm trends in children and young people in Greater Manchester from 2019 to 2023, finding a post-pandemic decrease overall but significant increases in younger girls.

## Contribution

The study provides novel insights into how self-harm incidence changed across pandemic phases and demographic groups in a specific regional population.

## Key findings

- Self-harm incidence decreased significantly in the post-pandemic phase compared to pre-pandemic for both males and females.
- Females aged 10–12 experienced the greatest increase in self-harm rates during pandemic phase 2, with rates nearly doubling.
- The rise in self-harm among females was most pronounced in the least deprived neighborhoods during pandemic phase 2.

## Abstract

The mental health of children and adolescents has declined in recent years. Self-harm is frequently an expression of this psychological distress.

To examine trends in self-harm incidence among 10–24-year olds between January 2019–December 2023.

We conducted time-series analyses of all incident episodes of self-harm among 10–24-year olds using the Greater Manchester Care Record. The observation period was split into four phases: pre-pandemic (1/2019–2/2020); pandemic phase 1 (3/2020–6/2021); pandemic phase 2 (7/2021–12/2022) and post-pandemic (1/2023–12/2023). Rate ratios by sex, age, ethnicity and Indices of Multiple Deprivation were modelled using negative binomial regression.

Self-harm incidence rates decreased significantly in the post-pandemic phase, compared with the pre-pandemic period (male—incident rate ratios (IRR) 0.72; 95% CI 0.62 to 0.84, female IRR 0.85; 95% CI 0.74 to 0.99). In females, this followed increased rates, rising by 18% in pandemic phase 2 (IRR 1.18; 95% CI 1.04 to 1.34). In males, rates decreased throughout the study period. Incidence rates were lowest for 10–12 year olds. However, the greatest increase was observed in this age group, with rates in pandemic phase 2 being almost two times that seen pre-pandemic for females (IRR 1.91; 95% CI 1.47 to 2.48). The change in rates among females was also most marked in the least deprived neighbourhoods, rising by more than 50% (IRR 1.54; 95% CI 1.21 to 1.95) in pandemic phase 2.

Our results indicate a decrease in self-harm incidence during 2023. Analysis by age group showed the greatest increase in rates in 10–12-year olds. Further research is needed to confirm these findings and to identify the mechanisms driving these trends.