# Association of screen time with attention-deficit/hyperactivity disorder symptoms and their development: the mediating role of brain structure

## TL;DR

This study finds that more screen time is linked to increased ADHD symptoms and thinner brain regions in children, suggesting a possible neural mechanism.

## Contribution

The study identifies specific brain regions and a partial mediation pathway linking screen time to ADHD symptoms.

## Key findings

- Screen time is associated with increased ADHD symptoms and reduced cortical thickness in specific brain regions.
- Total cortical volume partially mediates the relationship between screen time and ADHD symptoms at baseline.
- The findings suggest a potential neural mechanism for the link between screen time and ADHD symptom development.

## Abstract

The association among screen time, attention-deficit/hyperactivity disorder (ADHD) symptom development, and brain structure, and the neural mechanisms underlying the association between screen time and ADHD symptoms remain unclear. This study examines the relationships between the three using large-scale longitudinal data from the Adolescent Brain Cognitive Development (ABCD) study. Data on screen time, ADHD symptoms (measured via the Child Behavior Checklist), and brain structure were extracted from 10,116 children at baseline (ages 9–10) and 7880 children at a two-year follow-up. A linear mixed-effects model was used to assess the association between baseline screen time and changes in ADHD symptoms and brain structure after two years. Additionally, the mediating role of brain structure on the association between screen time and ADHD symptoms was examined. The results showed that screen time was associated with increased ADHD symptoms (β = 0.032, p = 0.001) and reduced cortical thickness in specific regions (right temporal pole: β = −0.036, false discovery rate (FDR)-corrected p = 0.020; left superior frontal gyrus: β = −0.028, FDR-corrected p = 0.020; and left rostral middle frontal gyrus: β = −0.030, FDR-corrected p = 0.020). Total cortical volume partially mediated the relationship between screen time and ADHD symptoms (β = 0.001, p = 0.023) at baseline. These findings suggest that screen time is associated with ADHD symptoms and brain structure, as well as their development, potentially providing insights into the neural mechanisms underlying the association between screen time and ADHD symptomatology.