The last few years have witnessed dramatic increases in presentations of eating disorders to mental health services for children and adults, which could relate to a greater number of people seeking help or to an increase in eating disorders at the population level. Aims: To evaluate the feasibility of online completion of a single module of the compare the Development and Well-Being Assessment (DAWBA) and to estimate the population prevalence of eating disorders among children and young people aged 6 to 19 years in 2017 and 2021, and to estimate the prevalence of eating disorders among emerging adults aged 20 to 23 years in 2021.

The Mental Health of Children and Young People in England was a cross-sectional survey of a probability sample that recruited 9,117 children and young people in 2017. Follow-up surveys were conducted in 2020, 2021 and 2022. The DAWBA, a multi-informant standardised diagnostic assessment, was completed by parents, teachers and young people aged 11 years or more in 2017. It covered all common mental health conditions, including eating disorders. In 2021 and 2022, parents and young people aged 11 years and over completed the five initial DAWBA screening items to assess eating difficulties as part of the follow-up questionnaire. In 2021, parents and young people who screened positive (n = 1030) were invited to complete the DAWBA eating disorder module online, and a small team of clinical raters reviewed their reports to assign diagnoses according to DSM 5.

There was a year delay in the provision of contact details to contact screen positives, and the response rate was 37% overall, comprising 28% of children aged 11 to 16 years, 23% of young people 17 to 25 years and 19% of parents initially invited. Our results illustrate the large and sustained increase in screen positives between 2017 and the follow-up surveys. We are currently quality-checking the clinical rating for the 2021 data, so we are close to a final prevalence of eating disorders for 2021.

There was an increase in the proportion of children aged 11–16 years with eating difficulties between 2017 (8.4% girls, 5.1 % boys) and 2021 (17.4 % girls, 8.4 % boys), which was maintained in 2021 and 2022 (17. 4% girls, 8.4 % boys). There were similar findings for young people aged 17 to 19 years (60.5% girls, 29.6% boys 2017, 76 % girls, 46% boys 2022)).

Inviting multiple informants provided data on more children and young people although many only had a single report from the person who screen positive. Wave 4 (2023) will integrate the eating disorder module into the original questionnaire to improve response rates. We suspect that the increase in the prevalence of eating disorders will be small despite the large and worrying increase in eating difficulties.