Characterizing the hierarchical structure of eating disorders and related mental disorders in youths across multiple timepoints

Background. The Hierarchical Taxonomy of Psychopathology (HiTOP) offers a promising dimensional framework to understand psychopathology, but its developmental applicability and the placement of eating disorders (EDs) within it remain unclear. This study aimed to map the hierarchical structure of youth psychopathology, with a specific focus on EDs, across late childhood into early adolescence. Methods. We used data from the Adolescent Brain Cognitive Development (ABCD) Study, to conduct exploratory (BassAckward) and confirmatory factor analyses on symptoms of 13 mental disorders at ages 9-10 (baseline; N=11,867), 11-12 (2-year; N=10,972), and 13-14 (4-year; N=8,355). We examined the hierarchical factor structure and tested for sex invariance at each timepoint.Results. A higher-order structure with Internalizing and Externalizing factors was identified across timepoints. However, the lower-order structure showed developmental differences. EDs consistently emerged as a distinct lower-order factor nested within the Internalizing spectrum. The phenotypic association between ED and obsessive-compulsive disorder (OCD) factors was notable (r ≈ .45–.50). While some specific factors such as oppositional defiant disorder, attention-deficit hyperactivity disorder, depression, and OCD were identified, the composition of anxiety-related factors changed across timepoints. Notably, the derived factor structures demonstrated measurement invariance across biological sex at each timepoint.Conclusion. Our findings support a developmentally sensitive HiTOP model in youth, where ED constituts an Internalizing subfactor by late childhood, with stronger symptom associations in early adolescence. The hierarchical approach captured both stability and meaningful developmental differences, underscoring the importance of integrating a developmental perspective into structural models of psychopathology.