Background and aims: With surges in digital technologies, concerns over adolescents? screen use have intensified. Previous studies often relied on self-reported screen time, neglecting the experiential and motivational aspects of different screen activities (e.g. social media, gaming, and smartphones), possibly leading to heterogeneous associations. This study aimed to examine whether the severity of problematic screen use, conceptualized as a continuous measure of screen-related functional impairment, plays a more central role in development than self-reported screen time or phone-checking frequency, and to explore its influence within the broader adolescent ecosystem (i.e. family conflict, peer involvement, and school participation). Methods: Cohort data were obtained from the Adolescent Brain Cognitive Development (ABCD) study Release 5.1. Screen use was obtained from self-report questionnaires, capturing both activity time and functional impairments. Among cross-sectional networks derived from 9,054 youth (4,272 girls, 47.18%) at 2-year follow-up (T2, ages 11-12 years) and 4,007 youth (1,896 girls, 47.32%) at 4-year follow-up (T4, ages 13-14 years), problematic use showed higher centrality than screen time and checking behavior, owing to stronger connections with behavioral tendencies. Cross-lagged-panel-network analyses of problematic use included 3,954 youth (1,863 girls, 47.12%). Results: Problematic use exhibited high out-strength, which was associated with worsening psychopathologies and environmental conditions. Conversely, problematic use at T4 appeared less influenced by factors at T2. Conclusion: This study underscores the pivotal role of problematic screen use, which showed greater centrality and stronger predictive effects on adolescent well-being than self-reported screen time, highlighting the need for policies and interventions addressing screen-related functional impairments to promote healthier screen habits in developing youth.  Kulcsszavak: problematic screen use, internet addiction, addictive behaviors, impulsive behaviors, adolescent development, network analysis