Associations between changes in behavioral difficulties and levels of problematic smartphone use in adolescents over a 1-year period

OBJECTIVES: The present longitudinal study investigates associations between changes in externalizing and internalizing behavioral difficulties and changes in problematic smartphone usage within the same 1-year period in healthy adolescents. METHODS: The project is part of the LIFE Child cohort study conducted in Leipzig, Germany. Ten- to 16-year-old adolescents (n = 363) provided information on behavioral difficulties [Strengths and Difficulties Questionnaire (SDQ)], the duration of daily smartphone use, and symptoms of smartphone addiction [Smartphone Addiction Proneness Scale (SAPS)] at two consecutive study visits, t1 and t2 (1 year after t1). In the first of two analysis phases, we applied linear regression analyses to assess cross-sectional associations between externalizing and internalizing behavioral difficulties and the duration of smartphone use and symptoms of smartphone addiction (at t1 and t2). In the second, we assessed associations between the changes measured in these variables over the period of a year. All associations were adjusted for age, sex, and soci-economic status. RESULTS: Children who reported prolonged periods of smartphone use or more symptoms of smartphone addiction exhibited significantly higher levels of externalizing and internalizing behavioral difficulties at t1 and t2. Further, children who increased their usage or developed addiction symptoms between t1 and t2 also developed more externalizing behavioral difficulties. We found the same tendencies in regard to internalizing behavioral difficulties, although the associations did not reach statistical significance. CONCLUSIONS: The present findings suggest that externalizing behavioral difficulties and problematic smartphone use are mutually dependent in the long term.