Excessive screen media use has been associated with poorer mental health outcomes among children and adolescents in various observational studies. However, experimental evidence to support this hypothesis has been limited. A recent cluster randomised clinical trial conducted in Denmark aimed to investigate the effects of a 2-week screen media reduction intervention on the mental health of children and adolescents.

Study Design and Participants

This study involved a prespecified secondary analysis of a cluster randomised clinical trial, including 89 families with 181 children and adolescents from 10 Danish municipalities in Southern Denmark. The study took place in the participants’ homes, providing a real-world setting for the intervention. Enrollment spanned from June 6, 2019, to March 30, 2021, with data analysis occurring between January 1 and November 30, 2023.

Intervention

Families were randomly assigned to either a screen media reduction group or a control group. The intervention required participants in the reduction group to limit their leisure-time screen media use to 3 hours per week or less per person and to hand over smartphones and tablets. This stringent limitation was designed to ensure high compliance.

Main Outcomes and Measures

The primary outcome measured was the difference between groups in the change in total behavioural difficulties, assessed using the Strengths and Difficulties Questionnaire (SDQ) at the 2-week follow-up. Mixed-effects tobit regression models were used to estimate results, and analyses were conducted on both an intention-to-treat and complete-case basis.

Results

The study included 89 families with a total of 181 children and adolescents:

• Intervention Group: 45 families, 86 children, mean age of 8.6 years (SD 2.7), and 42 girls (49%).
• Control Group: 44 families, 95 children, mean age of 9.5 years (SD 2.5), and 57 girls (60%).

Key Findings

• Behavioural Difficulties: There was a statistically significant between-group mean difference in the total difficulties score, favouring the screen media reduction intervention (−1.67; 95% CI, −2.68 to −0.67; Cohen d, 0.53).
• Internalising Symptoms: The greatest improvements were observed in internalising symptoms, such as emotional symptoms and peer problems (between-group mean difference, −1.03; 95% CI, −1.76 to −0.29).
• Prosocial Behavior: There was also a significant improvement in prosocial behaviour in the intervention group compared to the control group (between-group mean difference, 0.84; 95% CI, 0.39-1.30).

This secondary analysis of a randomised clinical trial indicates that a short-term reduction in leisure-time screen media use can positively affect the psychological symptoms of children and adolescents. Notably, the intervention mitigated internalising behavioural issues and enhanced prosocial behaviour. Further research is needed to determine whether these positive effects are sustainable over the long term.

Source: JAMA Network