Screen Media Use and Mental Health of Children and Adolescents: A Secondary Analysis of a Randomized Clinical Trial.

Importance: Excessive screen media use has been associated with poorer mental health among children and adolescents in several observational studies. However, experimental evidence supporting this hypothesis is lacking. Objective: To investigate the effects of a 2-week screen media reduction intervention on children's and adolescents' mental health. Design, Setting, and Participants: This prespecified secondary analysis of a cluster randomized clinical trial with a 2-week follow-up included 89 families (with 181 children and adolescents) from 10 Danish municipalities in the region of Southern Denmark. All study procedures were carried out in the home of the participants. Enrollment began on June 6, 2019, and ended on March 30, 2021. This analysis was conducted between January 1 and November 30, 2023. Intervention: Families were randomly allocated to a screen media reduction group or a control group. The 2-week screen media reduction intervention was designed to ensure a high level of compliance to the reduction in leisure-time screen media use. Participants allocated to the intervention group had to reduce their leisure-time screen media use to 3 hours per week or less per person and hand over smartphones and tablets. Main Outcomes and Measures: The main outcome was the between-group mean difference in change in total behavioral difficulties, measured by the Strengths and Difficulties Questionnaire at 2-week follow-up. Results were estimated using mixed-effects tobit regression models. Analyses were carried out as both intention to treat and complete case. Results: In the sample of 89 families including 181 children and adolescents (intervention group [45 families]: 86 children; mean [SD] age, 8.6 [2.7] years; 42 girls [49%]; control group [44 families]: 95 children; mean [SD] age, 9.5 [2.5] years; 57 girls [60%]), there was a statistically significant between-group mean difference in the total difficulties score, favoring the screen media reduction intervention (-1.67; 95% CI, -2.68 to -0.67; Cohen d, 0.53). The greatest improvements were observed for internalizing symptoms (emotional symptoms and peer problems; between-group mean difference, -1.03; 95% CI, -1.76 to -0.29) and prosocial behavior (between-group mean difference, 0.84; 95% CI, 0.39-1.30). Conclusions and Relevance: This secondary analysis of a randomized clinical trial found that a short-term reduction in leisure-time screen media use within families positively affected psychological symptoms of children and adolescents, particularly by mitigating internalizing behavioral issues and enhancing prosocial behavior. More research is needed to confirm whether these effects are sustainable in the long term. Trial Registration: ClinicalTrials.gov Identifier: NCT04098913.