To examine the effects of smartphone addiction on adolescents' internalizing and externalizing
behavior problems, this study consisted of 168 adolescents smartphone users from 5th to 8th grade in
Gyeonggi-do. The findings indicated that adolescents who were at the higher levels of smartphone
addiction showed the higher levels of internalizing and externalizing behavior problems. Specifically, the
relationship between subdomains of smartphone addiction (disturbance of adaptive functions, virtual life
orientation, withdrawal, and tolerance) and internalizing behavior showed that disturbance of adaptive
functions were positively related with somatic complaints of adolescents. The relationship between
subdomains of smartphone addiction and externalizing behavior showed that disturbance of adaptive
functions were positively related with aggressive and delinquent behaviors. The implications of these
findings are that we provide the education for adolescents on how to appropriately use the smartphone.
This study can also utilize the understanding of the problems and conflicts that could happen to the
adolescent developmental process.