Toward dimensional psychiatry in youth: A data-driven analysis of transdiagnostic internalizing symptoms in childhood and adolescence.

Categorical diagnostic systems for psychopathology, such as the DSM and ICD, have long been criticized for their limited validity and reliability. Dimensional models, like the Hierarchical Taxonomy of Psychopathology (HiTOP), offer an alternative by focusing on transdiagnostic dimensions that better capture the complexity of mental health disorders. While HiTOP's internalizing spectrum has been studied extensively in adults, its applicability and structure in children and adolescents remain less clear. Further, understanding sociopsychological indicators associated with internalizing dimensions in this age group could improve developmental psychopathological interventions. We analyzed data from 4,142 participants aged 5-21 (65.7% male; mean age = 10.46) from the Healthy Brain Network. Using exploratory and confirmatory factor analyses, we tested the internalizing structure proposed by HiTOP, with an additional focus on invariance across sex, age, and diagnostic groups. The hierarchical structure was tested through hierarchical CFA and the extended Bass-Ackward method. Structural equation modeling (SEM) examined latent factor relationships, and sociopsychological variables associated with the factors. A four-factor structure was identified: Distress, Nervousness, Social Fears, and Obsessions and Compulsions (OC). The model demonstrated partial invariance and strong fit indices. Sociopsychological variables, i.e., predictors and a quality of life indicator of the factors, included parental attitudes, discipline, bullying, and daily functioning. DSM categories and CBCL scores mapped well onto the latent factors. These findings suggest the potential clinical utility of a dimensional model for internalizing disorders in youth. Future studies should further examine the role of sociodemographic factors on dimensional constructs, explore predictive developmental trajectories longitudinally, and verify the structure of all HiTOP spectra across age groups to advance dimensional models in pediatric psychopathology research, as well as their implementation in clinical practice.