Temporal trends in eating disorder and self-harm incidence rates among adolescents and young adults in the UK in the 2 years since onset of the COVID-19 pandemic: a population-based study

Background: Self-harm and eating disorders share multiple risk factors, with onset typically during adolescence or early adulthood. We aimed to examine the incidence rates of these psychopathologies among young people in the UK in the 2 years following onset of the COVID-19 pandemic. Methods: We conducted a population-based study using the primary care electronic health records of patients aged 10–24 years in the UK Clinical Practice Research Datalink (CPRD). The observation period was from Jan 1, 2010, to March 31, 2022. We calculated the monthly incidence rates of eating disorders and self-harm according to the first record of each outcome. On the basis of antecedent trends between January, 2010, and February, 2020, negative binomial regression models were fitted to predict monthly incidence rates after the pandemic began in March, 2020. Percentage differences between observed and expected incidence were calculated to indicate changes since the onset of the pandemic, with stratification by sex, age, and deprivation quintile. Findings: The primary care health records of 9 184 712 patients aged 10–24 years (4 836 226 [52·7%] female patients and 4 348 486 [47·3%] male patients; n=1881 general practices) were included for analysis. The incidence rates of eating disorders and self-harm among girls were higher than expected between March 1, 2020, and March 31, 2022. The observed incidence of eating disorders was 42·4% (95% CI 25·7–61·3) higher than expected for girls aged 13–16 years, and 32·0% (13·3–53·8) higher than expected for girls aged 17–19 years, whereas other age groups showed little difference between observed and expected incidence. Similarly, the increase in self-harm incidence was driven by girls aged 13–16 years, for whom the observed incidence was 38·4% (20·7–58·5) higher than expected. By contrast, among boys in all age groups, the incidence rates of eating disorders and self-harm were lower than, or close to, the expected rates. Among boys, the observed incidence of eating disorders was 22·8% (9·2–34·4) lower than expected, and the observed incidence of self-harm was 11·5% (3·6–18·7) lower than expected. The estimated increases in eating disorder and self-harm incidence among girls aged 13–16 years were largely attributable to increases within less deprived communities. Interpretation: Although causes are uncertain, increased incidence of eating disorder diagnoses and self-harm among teenage girls in the UK during the first 2 years of the COVID-19 pandemic highlight an urgent need for intervention. Early identification of mental health difficulties by primary care clinicians is necessary. Timely access to treatments and sufficient support from general practitioners and mental health services needs to be available to manage presenting problems and to prevent exacerbations of conditions. Funding: National Institute for Health and Care Research.