Effect of Screen Time Exposure on Neurodevelopmental Outcome Among Toddlers: A Systematic Review of Longitudinal Evidence
TL;DR
Greater early screen exposure was associated with adverse neurodevelopmental outcomes, but high heterogeneity, imprecision and an observational evidence base prevent causal conclusions.
Abstract
Background: Screen-based media is increasingly present in early childhood, but the longitudinal association between toddler screen exposure and later neurodevelopment remains uncertain. This systematic review synthesized longitudinal evidence on screen-time exposure in toddlers and subsequent developmental outcomes. Methods: The review was registered in PROSPERO (CRD420261511593) and reported with reference to PRISMA 2020. PubMed, MEDLINE, PsycINFO and the Cochrane Library were searched for studies published from January 2020 to July 2026. Sixteen reports were included; one methods paper without exposure–outcome data did not contribute to the empirical synthesis. Of 15 empirical studies, five with usable effect-size information were pooled in an exploratory random-effects meta-analysis (DerSimonian–Laird estimator with a Hartung–Knapp-adjusted confidence interval) and ten were synthesized narratively. Sample size, participant age, screen-time measurement, follow-up, outcomes, effect estimates and confounder adjustment are tabulated for every study. Results: Higher early screen exposure was associated with higher odds of adverse neurodevelopmental outcomes (pooled OR = 2.04, 95% CI 1.25–3.34; Hartung–Knapp CI 1.05–3.96). Heterogeneity was substantial (I² = 89%, τ² = 0.26) and the 95% prediction interval was wide (0.33–12.54). Pooled estimates were OR = 2.18 (95% CI 0.78–6.10; k = 2) for ADHD/behavioural outcomes and OR = 1.93 (95% CI 1.16–3.21; k = 3) for autism-related outcomes, with no evidence of a subgroup difference (p = .83). Leave-one-out estimates ranged from 1.68 to 2.34. Narrative findings were mixed. A formal risk-of-bias assessment was not performed, and meta-regression was not feasible with five pooled studies. Conclusion: Greater early screen exposure was associated with adverse neurodevelopmental outcomes, but high heterogeneity, imprecision and an observational evidence base prevent causal conclusions. Balanced, developmentally appropriate media use and protection of caregiver–child interaction, sleep, play and physical activity are reasonable priorities while stronger longitudinal evidence is developed.