Excessive screen time is associated with mental health problems in US children and adolescents: physical activity and sleep as parallel mediators

The digitalization of modern society has introduced complex sociological challenges for children and adolescents by altering the structure of their daily lives and social interactions. These changes often result in increased sedentary behavior and disrupted routines, creating barriers to maintaining optimal mental health. This study explored the relationships between screen time and child and adolescent mental health problems, including anxiety, depression, behavior or conduct problems, and ADHD. Additionally, it examined whether physical activity, sleep duration, and bedtime regularity mediate these relationships. We analyzed data from 50231 children and adolescents aged 6 to 17 years from the United States National Survey of Children’s Health 2020-2021. The analysis utilized exact natural effect and structural equation modeling to investigate the mediating effects. Daily screen time $$\ge$$ 4 hours was associated with higher risks of anxiety (adjusted Odds Ratio [aOR] = 1.45, 95% CI: 1.33, 1.58), depression (aOR = 1.61, 95% CI: 1.40, 1.84), behavior or conduct problems (aOR = 1.24, 95% CI: 1.13, 1.37), and ADHD (aOR = 1.21, 95% CI: 1.11, 1.33). Physical activity was the strongest mediator, accounting for 30.9% to 38.9% of the association, followed by irregular bedtime (18.4% to 23.9%) and short sleep duration (4.16% to 7.24%). Prolonged screen time is associated with poorer mental health through the mediation of physical activity, bedtime regularity, and short sleep duration. Interventions should address these behavioral shifts by prioritizing physical activity and regular sleep routines to effectively mitigate mental health problems among young people.