Summary: A large, two-year longitudinal study of nearly 12,000 children found that greater daily screen time at ages 9–10 predicted an increase in ADHD symptoms two years later, even after accounting for initial symptom levels. Brain imaging showed that higher screen exposure was linked to smaller total cortical volume and altered development in brain regions important for attention, cognitive control, and reward processing.
These structural brain differences partly explained why children with more screen exposure experienced worsening ADHD symptoms over time, offering developmental neuroscience evidence that excessive screen use may interfere with typical brain maturation patterns commonly observed in ADHD.
Key Facts:
- Developmental Risk: Higher screen time at ages 9–10 predicted greater ADHD symptoms two years later.
- Brain Structure Impact: More screen exposure was associated with smaller overall cortical volume and altered growth in frontal and temporal brain regions.
- Mediation Effect: Total cortical volume partially mediated the relationship between screen time and ADHD symptom severity.
Source: University of Fukui
The digital environment has reshaped childhood: screens are now central to learning, play, socializing, and entertainment. Worldwide, daily screen time among children and adolescents has increased, a trend that accelerated during the COVID-19 pandemic when remote learning and social isolation became widespread.
While digital media provide important benefits, growing evidence links excessive screen use to sleep disruption, reduced physical activity, and behavioral difficulties. One concern is a connection between heavier screen use and more pronounced attention-deficit/hyperactivity disorder (ADHD) symptoms, which include challenges with attention, hyperactivity, and impulse control.
Past research documenting the link between screen time and ADHD-like symptoms has largely been cross-sectional, offering only snapshots that cannot establish developmental direction or underlying neural mechanisms. To address that gap, a team at the University of Fukui—led by Assistant Professors Qiulu Shou and Masatoshi Yamashita and Associate Professor Yoshifumi Mizuno—conducted a large-scale longitudinal analysis to examine how screen time relates to ADHD symptom trajectories and brain development.
Their peer-reviewed study was published in Translational Psychiatry (Volume 15) on October 31, 2025, and used data from the Adolescent Brain Cognitive Development (ABCD) study in the United States. The analysis followed 11,878 children who were 9–10 years old at baseline and reassessed outcomes two years later.
Using parent-reported behavior checklists and advanced magnetic resonance imaging (MRI) measures, the researchers modeled direct associations between baseline screen time and changes in ADHD symptoms and brain structure over the two-year interval. Statistical models adjusted for baseline symptom levels and other relevant covariates to isolate the developmental association.
Key outcomes showed that greater daily screen time at baseline predicted an increase in ADHD symptoms at follow-up. Concurrent neuroimaging findings linked higher screen exposure to smaller total cortical volume at baseline and to reduced volume in specific subcortical regions, such as the right putamen, which is implicated in reward processing and learning. Over two years, higher screen time was also associated with attenuated cortical thickening or slowed maturation in regions that support attention and executive functions, including the right temporal pole and areas in the left frontal gyrus.
Importantly, mediation analyses indicated that total cortical volume partially explained the association between screen time and ADHD symptoms at baseline. In practical terms, this suggests that the relationship between heavier screen use and greater symptom severity is at least partly linked to smaller cortical volume—a pattern consistent with delayed neurodevelopment often observed in ADHD.
By integrating behavioral and neuroimaging data over time, the study strengthens the evidence that excessive screen exposure in late childhood may contribute to altered brain maturation and increasing attention-related symptoms. The authors emphasize that these results do not prove causation in a strict experimental sense but provide robust longitudinal and mechanistic evidence supporting concerns about prolonged screen use during key developmental windows.
“Our findings contribute to growing concern about the effects of digital media on children’s mental and cognitive health,” said Dr. Yamashita, highlighting the neuroscientific basis for recommendations to moderate screen time in school-age children. The research team suggests that limiting excessive daily screen use could be an important component of promoting healthy brain development and reducing risk for worsening attention problems.
Overall, this work adds important longitudinal and neurobiological data to the literature, informing parents, educators, clinicians, and policy makers who design digital environments and guidelines for children’s media exposure.
Funding information
This research was supported by the Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research (KAKENHI) (Grant numbers: 24K16647, 21K02380), the Kawano Masanori Memorial Public Interest Incorporated Foundation for Promotion of Pediatrics (AY 2022), research grants from the University of Fukui (AY 2023), and the Life Science Innovation Center, University of Fukui (AY 2023).
Key Questions Answered:
A: Yes. In this large longitudinal sample, longer daily screen use at ages 9–10 predicted higher ADHD symptoms two years later, even after accounting for baseline symptom severity.
A: Higher screen time was associated with smaller total cortical volume at baseline and with altered development of cortical thickness in regions involved in attention, cognitive control, and reward processing.
A: Partially. Total cortical volume partially mediated the relationship, suggesting that slower or altered brain maturation contributes to increases in ADHD symptoms associated with greater screen exposure.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The original journal paper was reviewed in full for accuracy.
- Additional context and clarification were added by staff editors.
About this ADHD and neurodevelopment research news
Author: Yuuka Kawamoto
Source: University of Fukui
Contact: Yuuka Kawamoto – University of Fukui
Image: The image is credited to Neuroscience News
Original Research: Open access. “Association of screen time with attention-deficit/hyperactivity disorder symptoms and their development: the mediating role of brain structure” by Masatoshi Yamashita et al., Translational Psychiatry.
Abstract
Association of screen time with attention-deficit/hyperactivity disorder symptoms and their development: the mediating role of brain structure
This longitudinal study investigated associations among screen time, ADHD symptom trajectories, and brain structure using data from the Adolescent Brain Cognitive Development (ABCD) study. Researchers analyzed baseline data from 10,116 children aged 9–10 and a two-year follow-up sample of 7,880 children. Measures included parent-reported ADHD symptoms (Child Behavior Checklist) and structural MRI metrics.
Linear mixed-effects models showed that greater baseline screen time was associated with increased ADHD symptoms (β = 0.032, p = 0.001) and with reduced cortical thickness in specific regions (right temporal pole: β = −0.036, FDR-corrected p = 0.020; left superior frontal gyrus: β = −0.028, FDR-corrected p = 0.020; 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 at baseline (β = 0.001, p = 0.023).
These findings indicate that higher screen time is associated with ADHD symptom severity and with brain structural differences and developmental trajectories that may underlie those behavioral effects.