Screen Time, Sociodemographic Factors, and Psychological Well-Being Among Young Children.

Importance: Young children's screen time increased during the COVID-19 lockdown in 2020, but it is unknown whether their screen time returned to prepandemic levels in 2021. Knowledge of the relationship between screen time and child development and health will inform prevention and intervention targets and strategies. Objective: To evaluate screen time by family income and race and ethnicity in the prepandemic (ie, 2018, 2019) and pandemic (ie, 2020, 2021) periods and to examine the relationship between screen time and psychological well-being among young children in the US. Design, Setting, and Participants: Cross-sectional population-based web or mail survey study of 2018-2021 National Survey of Children's Health participants aged 6 months to 5 years. Exposure: Daily screen time (<1, 1, 2, 3, or ≥4 h/d) reported by participants' primary caregivers. Main outcomes and Measures: Flourishing and externalizing behaviors, as indicators of psychological well-being. All analyses were weighted, accounting for the complex survey sample design. Results: Of the 48 775 participants (50.7% female), the proportion of those with high screen time (defined as ≥1 h/d for children aged 6 months-1 year and ≥2 h/d for children aged 2-5 years) was 48.5% (95% CI, 46.3%-50.7%) in 2018, 49.2% (95% CI, 47.0%-51.5%) in 2019, 55.3% (95% CI, 53.4%-57.2%) in 2020, and 50.0% (95% CI, 48.3%-51.6%) in 2021. Among children living in poverty (federal poverty level <100%), the proportion of those with high screen time was 48.7% (95% CI, 42.8%-54.6%) in 2018, 52.0% (95% CI, 45.4%-58.6%) in 2019, 60.9% (95% CI, 55.4%-66.4%) in 2020, and 58.9% (53.7%-64.1%) in 2021. Adjusted odds ratio of flourishing was 0.66 (95% CI, 0.51-0.85), 0.81 (95% CI, 0.66-0.99), 0.68 (95% CI, 0.52-0.88), and 0.53 (95% CI, 0.42-0.69) for less than 1, 2, 3, and 4 or more hours per day vs 1 hour per day of screen time, respectively, among children aged 3 to 5 years. No association between screen time and flourishing was found among children aged 6 months to 2 years. An adjusted externalizing behavior score was higher by 0.2 points (95% CI, -0.1 to 0.5), 0.5 points (95% CI, 0.3 to 0.8), 1.3 points (95% CI, 1.0 to 1.6), and 2.1 points (95% CI, 1.7 to 2.5) for less than 1, 2, 3, and 4 or more hours per day vs 1 hour per day of screen time, respectively, among children aged 3 to 5 years. Conclusions and Relevance: In this multiyear cross-sectional study of a representative sample of young children in the US, the increased prevalence of high screen time in 2020 returned to prepandemic levels in 2021; however, it remained elevated in children living in poverty. Two hours or more of daily screen time was associated with lower psychological well-being among preschool-aged children.