Prospective associations of screen time at age 2 with specific behavioral subscales at age 3: a cohort study.

This study, conducted within the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study in Japan, investigates the prospective association between children's screen time (ST) at age 2 and behavioral problems at age 3, specifically internalizing and externalizing behaviors assessed by the Child Behavior Checklist for Ages 1½–5 (CBCL). After adjusting for behavioral problem scores at age 2 and various covariates, greater ST at age 2 was found to be significantly associated with increased risks of emotionally reactive (an internalizing subscale) and aggressive behaviors (an externalizing subscale) at age 3. Associations with other subscales such as withdrawn, somatic complaints, anxious/depressed, and attention problems were not significant after adjustment, suggesting that long ST may be a characteristic of children with these behavioral problems rather than a causal factor. The study highlights the importance of distinguishing specific behavioral subscales in understanding the impact of early ST and notes limitations including reliance on parent-reported ST and lack of data on screen content.