Diagnosing eating disorders can be difficult and few people with the disorder receive specialist services despite the associated high morbidity and mortality.

To examine the burden of eating disorders in the population in terms of incidence, comorbidities and survival.

We used linked electronic health records from general practitioner and hospital admissions in Wales, UK within the Secure Anonymised Information Linkage (SAIL) databank to investigate the incidence of new eating disorder diagnoses. We examined the frequency of comorbid diagnoses and prescribed medications in cases and controls in the 2 years before and 3 years after diagnosis, and performed a survival analysis.

A total of 15 558 people were diagnosed with eating disorders between 1990 and 2017. The incidence peaked at 24 per 100 000 people in 2003/04. People with eating disorders showed higher levels of other mental disorders (odds ratio 4.32, 95% CI 4.01–4.66) and external causes of morbidity and mortality (odds ratio 2.92, 95% CI 2.44–3.50). They had greater prescription of central nervous system drugs (odds ratio 3.15, 95% CI 2.97–3.33), gastrointestinal drugs (odds ratio 2.61, 95% CI 2.45–2.79) and dietetic drugs (odds ratio 2.42, 95% CI 2.24–2.62) before diagnosis. These excess diagnoses and prescriptions remained 3 years after diagnosis. Mortality was raised compared with controls for some eating disorders, particularly in females with anorexia nervosa.

Incidence of diagnosed eating disorders is relatively low in the population but there is a major longer term burden in morbidity and mortality to the individual.

Mental disorders in children and adolescents have an impact on educational attainment.

To examine the temporal association between attainment in education and subsequent diagnosis of depression or self-harm in the teenage years.

General practitioner, hospital and education records of young people in Wales between 1999 and 2014 were linked and analysed using Cox regression.

Linked records were available for 652 903 young people and of these 33 498 (5.1%) developed depression and 15 946 (2.4%) self-harmed after the age of 12 but before the age of 20. Young people who developed depression over the study period were more likely to have achieved key stage 1 (age 7 years) but not key stage 2 (age 11) (hazard ratio (HR) = 0.79, 95% CI 0.74–0.84) milestones, indicating that they were declining in academic attainment during primary school. Conversely, those who self-harmed were achieving as well as those who did not self-harm in primary school, but showed a severe decline in their attainment during secondary school (HR = 0.72, 95% CI 0.68–0.78).

Long-term declining educational attainment in primary and secondary school was associated with development of depression in the teenage years. Self-harm was associated with declining educational attainment during secondary school only. Incorporating information on academic decline with other known risk factors for depression/self-harm (for example stressful life events, parental mental health problems) may improve risk profiling methods.

None.