Abstract
OBJECTIVE: This study investigates the reciprocal, longitudinal relationship between smartphone dependence and externalizing behavior problems in children. METHODS: A total of 379 school-aged children (7-12 years old) were assessed using the Smartphone Overdependency Observer Scale and the Korean Version of the Child Behavior Checklist for Ages 6-18 at four six-month intervals from June 2021 to June 2022. Among them, 338 children completed at least two assessments. An autoregressive cross-lagged model was employed to examine the bidirectional relationships and temporal stability between smartphone overdependence and externalizing behavior problems while controlling for gender, age, and baseline internalizing behavior problems. RESULTS: Both variables demonstrated significant autoregressive effects, indicating stability over time. Cross-lagged analysis revealed that higher smartphone dependence predicted increased externalizing behavior problems in subsequent periods while externalizing behavior problems did not predict future smartphone dependence. CONCLUSION: Smartphone dependence appears to contribute to externalizing behavior problems in children, highlighting the critical need for early interventions that promote healthy digital habits to mitigate behavioral challenges.