Reciprocal longitudinal associations between symptoms of eating disorders, self-harm and suicidal ideation.

BackgroundEating disorders are severe psychiatric conditions associated with high mortality rates, particularly among young people. These disorders often co-occur with self-harm and suicidal ideation, yet the temporal dynamics between these variables remain poorly understood. AimsThis study aims to elucidate the longitudinal associations between eating disorder symptoms, self- harm, and suicidal ideation using structural equation modelling. MethodRepeated measures of these phenotypes were used to construct a hypothetical model that includes cross-path analyses within and between the variables in two cohorts: the Twins Early Development Study (TEDS; ages 16, 21 and 26; N=5,196), representing a general population sample, and the Covid-19 Psychiatry and Neurological Genetics study (COPING; data collected between June 2020 and July 2021; N=490), which focused on individuals with a history of anxiety or depression. In the TEDS cohort, symptoms of eating disorders, self-harm, and suicidal ideation showed limited continuity across adolescence and young adulthood, with peak symptom severity at age 21. ResultsCross-domain associations revealed that both self-harm and suicidal ideation at age 21 were more strongly associated with eating disorders at 26 than the reverse. In contrast, the COPING cohort exhibited more stability in symptoms over time but showed minimal cross-domain effects. ConclusionsThe effects of self-harm and suicidal ideation on eating disorders in early adulthood are stronger than the influence of disordered eating on suicidality.