The escalating burden of mental health problems among youth in the U.S. suggests that new approaches to psychopathology are urgently needed. Consistent with the National Institute of Mental Health Research Domain Criteria (RDoC), which prioritizes multi-level, dimensional data to improve traction on etiology and to identify new intervention targets, advanced quantitative methods discerning the underlying structure of psychopathology will accelerate innovations. Replicated evidence shows that a general factor (p-factor) nonspecifically confers liability to psychopathology, independent of specific internalizing and externalizing factors, and also economically characterizes their covariation. Careful evaluation of the p-factor in youth and its associations with external criteria is needed given age-related effects on psychopathology and concerns over statistical bias favoring bifactor models. Study I of this dissertation supported a bifactor model in youth with general and specific factors of psychopathology which were uniquely associated with independent measures of academic, social, and global functioning.

Next, social risk factors and their underlying processes are associated with general and specific forms of psychopathology, as suggested by the system of social processes included in the RDoC construct matrix. To elucidate specific targets for intervention and to inform a nascent evidence base, Study II of this dissertation empirically examined patterns of digital media use with adolescent development. Increasing concerns among parents, educators, and healthcare providers parallel recent evidence that frequent digital media use is positively associated with concurrent and prospective psychopathology in adolescents. In addition to simple bivariate associations, identifying their underlying mediators will reveal logical intervention targets. Study II implicated specific online behaviors (i.e., upward social comparison, receiving negative feedback, risky self-presentation) as unique mediators of the concurrent association of frequency of digital media use with transdiagnostic mental health problems.

Lastly, consistent with the RDoC initiative’s prioritization of physiological data for the study of affective systems, biological approaches must be integrated into models of the development of youth psychopathology. Measures of respiratory sinus arrythmia (RSA) during emotionally-challenging tasks are associated with youth internalizing and externalizing psychopathology; RSA is a plausible transdiagnostic biomarker of psychopathology. Study III of this dissertation explored the covariation of internalizing and externalizing problems in school-age girls with RSA during a fear conditioning task. Although unrelated with indicators of psychopathology, likely due to the small sample size, significant variability in RSA was observed and it remains a promising biomarker to be leveraged diversely across intervention and basic science contexts, including predicting risk and resilience processes.