Longitudinal Relationship Between Smartphone Dependence and Externalizing Behavior Problems: An Autoregressive Cross-Lagged Model

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.