Digital Media, Genetics, and Risk for ADHD Symptoms in Children: A Longitudinal Study.

Background: Children spend significant amount of time using digital media (DM), and longer exposure may increase attention-deficit/hyperactivity disorder (ADHD)-related symptoms, although findings are mixed. We investigated longitudinal association between different types of DM use and ADHD-related symptoms in school-aged children, accounting for genetic predisposition and socioeconomic status. Methods: This study included children from the Adolescent Brain and Cognitive Development Study, followed annually for four years. Estimated time spent on social media, video games, and television/videos was self-reported using Youth Screen Time Survey. ADHD-related symptoms were assessed at each visit with the parent-reported Child Behaviour Checklist. Genetic predisposition was estimated using a polygenic risk score for ADHD (PGS-ADHD). Results: The study included 8324 children (53% boys; mean age: 9.9 years). On average, children spent 2.3 hours/day watching television/videos, 1.4 hours/day on social media, and 1.5 hours/day playing video games. Average social media use was associated with increased inattention symptoms over time (β [SE], 0.03 [0.01]; P<0.001), with a cumulative four-year effect of β=0.15 [SE]=0.03; P<0.001). No associations were found between playing video games or watching television/videos and ADHD-related symptoms. The association between social media use and inattention symptoms was not moderated by sex, ADHD diagnosis, PGS-ADHD, or ADHD medication status. Inattention symptoms were not associated with increased social media use over time. Conclusion: Social media use was associated with an increase in inattention symptoms in children over time. Although the observed effect size was small, it could have significant consequences if behavior changes occur at the population level.