Higher screen time linked to ADHD symptoms and altered brain development

Researchers provide crucial insights into the underlying neural mechanisms associating screen time and behavioral issues among school-aged children

University of Fukui

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This study found evidence that children with higher screen time exhibit measurable differences in the volume and thickness of several key brain areas.

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Credit: Dr. Yoshifumi Mizuno from the University of Fukui, Japan

The digital age has fundamentally reshaped childhood, making screens an integral part of learning, socialization, and entertainment. Globally, screen time among adolescents has surged, accelerated by the isolation and remote learning periods during the COVID-19 pandemic. Although digital screens are essential tools, their excessive use has been linked to problems such as disrupted sleep, reduced physical activity, and behavioral symptoms.

Scientists have pointed out a correlation between higher screen time and more severe attention-deficit/hyperactivity disorder (ADHD) symptoms—a condition marked by difficulties with attention, hyperactivity, and impulse control. Unfortunately, existing evidence supporting the above correlation was obtained mainly through cross-sectional studies, which can only offer a single ‘snapshot in time’ across the researched population. Thus, our understanding of whether and how screen time influences the development of ADHD, as well as its underlying neural mechanisms affecting brain development, remains limited.

Aiming to bridge this gap, a research team led by Assistant Professor Qiulu Shou, Assistant Professor Masatoshi Yamashita, and Associate Professor Yoshifumi Mizuno, all affiliated to the University of Fukui, Japan, conducted a large-scale study on the impact of screen time on brain development and ADHD symptoms. Their study was published in Volume 15 of the journal Translational Psychiatry on October 31, 2025.

The researchers used data from the large-scale Adolescent Brain Cognitive Development study in the United States, tracking 11,878 children initially aged 9 to 10 years over a 2-year period. “This study is the first to examine the relationship between screen time, ADHD symptoms, and brain structure from a developmental perspective using such a large-scale database,” explains Dr. Shou.

Based on advanced magnetic resonance imaging data and parent-reported behavior assessments, the team carefully analyzed the direct associations between screen time and ADHD symptom severity, its development over 2 years, and the resulting changes in brain structure. The results provided clear evidence of a developmental link: longer daily screen time at baseline was a significant predictor of increased ADHD symptoms after 2 years, even after controlling for initial symptom severity levels.

Notably, screen time was also associated with developmental abnormalities in multiple key brain structures. At baseline, it was linked to a smaller total volume of the cortex and reduced volume in a region known as the right putamen, which plays a key role in language learning, addiction, and reward-related processes. After 2 years, screen time was associated with hindered development of cortical thickness in regions vital for cognitive functions, including the right temporal pole and specific areas of the left frontal gyrus.

One of the findings of this study centered on the role of brain structure as a mediator of ADHD symptoms. Statistical analyses suggest that total cortical volume partially mediates the relationship between screen time and ADHD symptoms at baseline. In essence, this means that the observed association between longer screen time and greater ADHD symptom severity is, at least in part, explained by the observed smaller cortical volume. The team suggests that excessive screen exposure may contribute to a delayed brain maturation pattern that is often observed in children with ADHD.

By providing evidence of a neural mechanism, this study bolsters our understanding of the link between digital habits and behavior in developing children. “Our work provided some evidence toward growing concern about the association between digital media exposure and children’s mental and cognitive health,” comments Dr. Yamashita. “The results provide some neuroscientific evidences for the need to control screen time.”

Overall, this study adds to the existing literature that strongly suggests reducing screen exposure among school-aged children is pivotal to their development. Dr. Mizuno concludes, “Our findings provide evidence that longer screen time is associated with increased ADHD symptoms and brain structural development. The findings of our research enhance our understanding of the link between screen time and ADHD symptoms, as well as the neural mechanisms underlying ADHD.”

To conclude, this study paves the way for further investigation that may guide both the technology industry and the educational sector toward designing digital environments that support, rather than hinder, children’s cognitive growth.

 

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About The University of Fukui, Japan

The University of Fukui is a preeminent research institution with robust undergraduate and graduate schools focusing on education, medical and science, engineering, and global and community studies. The university conducts cutting-edge research and strives to nurture human resources capable of contributing to society on the local, national, and global level.

Website: https://www.u-fukui.ac.jp/eng/

About Assistant Professor Qiulu Shou from University of Fukui, Japan

Dr. Qiulu Shou serves as an Assistant Professor at the Research Centre for Child Mental Development, University of Fukui, Japan. Additionally, she is also associated with the United Graduate School of Child Development, The University of Osaka, Kanazawa University, Hamamatsu University School of Medicine, and Chiba University. Her areas of expertise include pediatric brain development, neurodevelopment, and developmental disorders of the brain.

About Assistant Professor Masatoshi Yamashita from University of Fukui, Japan

Dr. Masatoshi Yamashita obtained his master’s and Ph.D. degrees in Psychology from Tezukayama University in 2014 and 2016, respectively. He joined University of Fukui in 2022, where he currently serves as an Assistant Professor at the Faculty of Advanced Research Center for Child Mental Development and the United Graduate School of Child Development. He specializes in experimental psychology, general neuroscience, and lifespan development.

About Associate Professor Yoshifumi Mizuno from University of Fukui, Japan

Dr. Yoshifumi Mizuno specializes in magnetic resonance imaging-based neuroimaging research on attention-deficit/hyperactivity disorder (ADHD). From 2019 to 2021, he served as a JSPS Overseas Research Fellow at the Department of Psychiatry and Behavioral Sciences, Stanford University, USA, where he contributed to advancing the understanding of ADHD’s neural mechanisms. Currently, Dr. Mizuno leads groundbreaking research as the Principal Investigator of the Division of Affective and Cognitive Development at the Research Center for Child Mental Development, University of Fukui, Japan.

Funding information

This project was funded by the Japan Society for the Promotion of Science through Grants-in-Aid for Scientific Research (KAKENHI) (Grant numbers: 24K16647, 21K02380), 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).

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Journal

Translational Psychiatry

DOI

10.1038/s41398-025-03672-1 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

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

BAN ECT

New global study finds ECT linked to wide range of severe effects

International survey reports on 25 adverse effects of electroconvulsive therapy besides memory loss, calling for rehabilitation for damaged patients

University of East London

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An international survey has revealed that electroconvulsive therapy (ECT) causes a much broader and more damaging range of side effects than previously acknowledged, challenging long-held claims about its safety.

The study – The adverse effects of electroconvulsive therapy beyond memory loss: an international survey of recipients and relatives, published in the International Journal of Mental Health – was led by Professor John Read of the University of East London. The paper reports the responses of 747 people who had received ECT and 201 relatives or friends across 37 countries, making it the largest study of its kind to date.

Seventeen of the 25 adverse effects listed in the survey were reported by more than half of both groups. Eight were reported by over two-thirds, including losing train of thought (88%), difficulty concentrating (86%), fatigue (80%) and emotional blunting (76%). Many participants also cited relationship problems, loss of independence and difficulty navigating or finding words. The first four of these effects were described as “severe” by at least 30% of respondents.

Women, people receiving bilateral ECT, and those who had undergone multiple courses were more likely to experience serious and lasting harm. Crucially, the research found no evidence that modern ECT is safer than earlier forms, contradicting frequent claims that contemporary methods reduce risk.

Professor John Read, Professor of Clinical Psychology, said,

“It is a sad indictment of ECT psychiatrists that there has been no interest in establishing the full range of adverse effects from this treatment in the 80 years it has been in use. Given that we don’t even know whether it is better than a placebo, it is time to suspend this procedure pending better research, into both efficacy and safety.”

Co-author and ECT survivor Lisa Morrison said,

“If any other patient group reported these serious and permanent devastating effects from a medical treatment, there would be immediate action. Yet people who are harmed by ECT continue to be silenced and ignored without access to rehabilitation for their injuries.”

The authors urge mental health services to ensure full disclosure of risks before treatment and to offer rehabilitation to those affected. They conclude that the evidence now demands a fundamental re-examination of ECT’s place in modern psychiatry.

The paper concluded:

“Researchers and mental health staff should pay attention to a broader range of potential adverse effects than memory loss, to facilitate fully informed consent, the minimisation or those effects where possible, and, where not possible, referral to rehabilitation programmes.”

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Journal

International Journal of Mental Health

DOI

10.1080/00207411.2025.2576946 

Method of Research

Survey

Subject of Research

People

Article Title

The adverse effects of electroconvulsive therapy beyond memory loss: an international survey of recipients and relatives

Article Publication Date

19-Nov-2025

 

New super pest combines broad spectrum of microbes

In addition to pathogens, the reed leafhopper hosts symbiotic bacteria that could play a role in adapting to new host plants

Max Planck Institute for Chemical Ecology

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The reed leafhopper (Pentastiridius leporinus) was listed as "endangered" on Germany's Red List for a long time. However, in recent years, it has become a super pest, infesting more and more crops. The picture shows the leafhopper on a sugar beet leaf.

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Credit: Benjamin Weiss, Max Planck Institute for Chemical Ecology

The reed leafhopper (Pentastiridius leporinus) was originally a specialist, limited exclusively to reed grass as a food source. Within a few years, however, it developed into a dangerous pest that attacks not only reed grass but also sugar beets, potatoes, carrots, and onions.  Although the insect itself causes only minor damage to plants, it transmits harmful bacteria that cause plant diseases and lead to massive crop failures—especially in sugar beet and potato production. Two bacterial pathogens are responsible for this: one causes SBR (Syndrome Basses Richesses, or low sugar content syndrome), and the other causes stolbur.

Researchers from the Max Planck Institute for Chemical Ecology in Jena and the Fraunhofer Institute for Molecular Biology and Applied Ecology in Giessen investigated how this insect spread so rapidly and what role its microbial flora might have played in the process. The researchers used state-of-the-art sequencing methods and fluorescence in situ hybridization to identify the microbial community and show where it resides in the insect's body.

"We showed that the reed leafhopper hosts at least seven species of bacteria. The leafhopper appears to be completely dependent on three of these species. These symbionts inhabit specific organs and are passed down through generations alongside the eggs. The bacteria contribute to the leafhopper's nutrition by producing essential amino acids and vitamins. Two other bacteria cause the plant diseases SBR and stolbur. These pathogens are transmitted from leafhoppers to host plants, contributing largely to the harmful effects of leafhoppers. The significance of the two remaining bacteria remains unclear," says lead author Heiko Vogel, summarizing the most important findings. Vogel heads the Host Plant Adaptation and Immunity project group in the Department of Insect Symbiosis.

The two plant-pathogenic bacteria are Candidatus Arsenophonus phytopathogenicus, which causes SBR, and Candidatus Phytoplasma solani, which causes stolbur disease. The research team found five other bacterial species in various organs of the reed leafhopper. The genera Purcelliella, Karelsulcia, and Vidania are mutualists that enable a plant-sap diet. These genera compensate for nutritional deficiencies by providing essential amino acids and B vitamins, or by contributing to the biosynthesis of these substances. The significance of the genera Rickettsia and Wolbachia for the insect host remains speculative. "We were particularly amazed by the complexity of the different microbes, as well as by the fact that Rickettsia bacteria can be found in the cell nuclei of many leafhopper tissues," says Martin Kaltenpoth, head of the Department of Insect Symbiosis at the Max Planck Institute.

How the reed planthopper is able to adapt to the highly diverse defense mechanisms of its host plants is still unknown. However, both the bacteria that cause plant diseases and the symbionts could play a role here.

The results of the study serve as the starting point for developing targeted strategies to manipulate the reed leafhopper's bacterial symbionts. One approach is to inhibit the production of specific salivary proteins in the leafhoppers using RNA interference. Double-stranded RNA (dsRNA) is injected against the target gene to accomplish this. "We are currently developing dsRNA-based sprays in Giessen for the environmentally friendly and targeted control of reed leafhoppers and other pests," says Andreas Vilcinskas from the Fraunhofer Institute for Molecular Biology and Applied Ecology.

Further studies are planned to better understand the role of the reed leafhopper's microbial partners and their interactions. These studies should reveal new approaches to combating this devastating agricultural pest.             

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Journal

mBio

DOI

10.1128/mbio.03103-25 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

A multi-partner symbiotic community inhabits the emerging insect pest Pentastiridius leporinus

Article Publication Date

22-Nov-2025

 

Extreme-matter research secures renewal

Collaborative Research Centre 211 receives about 10 million euros for its third phase

Bielefeld University

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Simulation of a neutron-star merger: The consortium investigates the properties of extremely dense matter under such conditions.

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Credit: Breu, Radice, Rezzolla

The German Research Foundation (DFG) is funding the transregional Collaborative Research Centre (CRC/TRR) 211 ‘Strong-Interaction Matter under Extreme Conditions’ for another 3.5 years. The DFG announced the decision today (21 November 2025). The consortium of the universities of Bielefeld, Darmstadt, and Frankfurt am Main will receive around 10 million euros from January 2026 for the third funding phase.

Since July 2017, the CRC/TRR 211 has been investigating the most extreme states of matter in the Universe. The researchers explore what happens when ordinary matter is heated to extremely high temperatures and subjected to enormous pressure. Under such conditions, protons and neutrons dissolve into their constituents – quarks and gluons. These states occur in neutron-star mergers, in heavy-ion collisions at particle accelerators, and in the early Universe shortly after the Big Bang.

‘This Collaborative Research Centre is an outstanding example of top-level theoretical research carried out in the context of major international experiments,’ says Professor Dr Angelika Epple, Rector of Bielefeld University. ‘The fact that the DFG is now funding this consortium for the third time speaks for itself.’

‘The renewed funding is a recognition of our team’s excellent work,’ says particle physicist Professor Dr Sören Schlichting of Bielefeld University, who will serve as spokesperson and lead the CRC in the next phase. A total of 26 principal investigators and another 76 researchers will collaborate in the new funding period within the Transregio. ‘We combine fundamental theoretical research with applications in cosmology, heavy-ion physics, and astrophysics – a globally unique constellation,’ Schlichting says.

Achievements of the second funding period

In the previous, second funding phase, the consortium published more than 250 scientific papers and organised two major international conferences. The researchers gained new insights into the phase diagram of quantum chromodynamics (QCD) – a kind of map showing the states in which matter exists at different temperatures and densities. They developed methods to infer the properties of extreme matter from experiments at particle accelerators and from observations of neutron-star mergers.

‘Our work provides the theoretical foundations needed to interpret experimental data with precision,’ explains nuclear and particle physicist Professor Dr Guy Moore of TU Darmstadt, the current spokesperson of the CRC and future deputy spokesperson. ‘This is crucial for the major international measurement campaigns that are currently under way or planned.’

Quantum computers and gravitational waves

In the new funding period, the consortium will investigate, among other things, how matter behaves at extremely high density and which changes of state occur under such conditions. The researchers will also test new theoretical approaches, including methods that use quantum computers.

‘We link fundamental particle physics to observable phenomena,’ says nuclear physicist Professor Dr Hannah Elfner of Goethe University Frankfurt, deputy spokesperson of the CRC. ‘Our research addresses fundamental questions about the development of the Universe – from the behaviour of the  elementary constituents of matter to the structure of neutron stars.’

The consortium brings particle physics to the public through formats such as ‘Shots of Science’ in an Irish pub or through talks at schools. In January, the team is expected to present the CRC’s research in a public lecture in the ‘Physics on Saturday’ series.