The Impact of Smartphone Over-Dependence on Depression among Adolescents: Focusing on the Mediating Effect of Aggression and the Moderated Mediating Effect of Student-Teacher Relation

Objectives This study examined the mediating effect of aggression and the moderated mediating effect of student-teacher relations on the relationship between smartphone over-dependence and depression among first-year middle school students. Methods Data obtained from the 2018 Children and Adolescent Panel which covered 2,541 middle school students were analyzed using PROCESS macro Model 4 for the mediating effect and Model 14 for the moderated mediating effect, and the bootstrapping method was employed to verify the significance of each model effect. Results It was found that aggression has a partial mediating effect in the relationship between smartphone overdependence and depression. In other words, smartphone over-dependence not only directly affects depression, but also indirectly through aggression. In addition, it was found that the more positive the teacher-student relationship perceived by students was, the less the effect of aggression on depression. Conclusions The results of this study suggest that it is necessary not only to intervene in smartphone over-dependence and aggression caused by it but also to consider the importance of the relationship between teachers and students to prevent mental health problems like depression among adolescents.