Eating disorder symptoms do not just disappear: the implications of adolescent eating-disordered behaviour for body weight and mental health in young adulthood.

This study reports the outcomes of childhood and adolescent eating-disordered behaviour on the development of body mass index (BMI) and psychological functioning in young adulthood in a population-based sample in Germany (the BELLA study). Information at baseline and follow-up was obtained through a telephone interview and mailed self-report questionnaires. At both measurement points, BMI, eating disorder symptoms (SCOFF questionnaire), and symptoms of depression and anxiety were assessed in the same cohort of 771 participants (n = 420 females, n = 351 males). The age range at baseline was 11-17 years, and the age range at follow-up was 17-23 years. High scores for eating-disordered behaviour in childhood or adolescence significantly predicted eating-disordered behaviour in young adulthood (multiplicative effect estimate: 1.31; 95 % CI: 1.2-1.42, p < 0.0001), although there was a decline in prevalence (from 19.3 to 13.8 %, p = 0.002) and severity (mean decrease in SCOFF 0.07, 95 % CI: -0.01-0.14, p = 0.06). After accounting for potentially confounding variables at baseline (SES, probands' BMI, parental BMI, depressive symptoms), participants with more eating disorder symptoms at baseline had a higher risk of developing overweight (odds ratio (OR): 1.58; 95 % CI: 1.19-2.09, p = 0.001), obesity (OR = 1.67; 95 % CI: 1.03-2.66, p = 0.03), and depressive symptoms at follow-up (additive effect estimate: 0.45; 95 %CI: 0.19-0.7, p = 0.0006). Early symptoms of depression showed a significant relationship with extreme underweight in young adulthood (OR = 1.13; 95 %CI: 1.01-1.25, p = 0.02). The high stability of eating disorder symptoms and the significant association with overweight and worse mental health in adulthood underscore the need for early detection and intervention during childhood and adolescence. Youth with depression should be monitored for the development of restrictive eating disorders.