Bidirectional Dynamics of Dual Systems and Problematic Internet Use in Children and Adolescents: A Person-Centered Perspective.

OBJECTIVE: Problematic Internet Use (PIU) is a critical public health issue, especially among children and adolescents. The Dual Systems Model posits that imbalances between reward processing and self-control systems increase PIU vulnerability, with potential reciprocal effects of PIU on these systems. However, previous studies have primarily employed variable-centered approaches, neglecting within-system heterogeneity, and longitudinal studies on bidirectional relationships have mostly focused on single system, with limited evidence in children. METHODS: The present study fills these research gaps by utilizing person-centered approaches to explore bidirectional relationships in 1341 children (9-11 years) and adolescents (13-16 years). A 1-year longitudinal survey measuring reward sensitivity, self-control, and PIU was conducted, combined with latent profile transition analysis and supervised machine learning. RESULTS: The results showed developmental similarities and differences. First, dual systems patterns predicted PIU in both age groups, but the underlying mechanisms were different. Low reward sensitivity and low self-control in children and adolescents increased PIU risk, while adolescents also uniquely affected by high reward sensitivity and low self-control. Second, PIU only reduced reward sensitivity and self-control over time in children. CONCLUSIONS: The present study enriches the Dual Systems Model by demonstrating bidirectional relationships from a person-centered perspective and informs tailored PIU interventions based on developmental stage and dual-system profiles.