18 Dec Karolinska Institutet Finds Children with Higher Social Media Use Showed Gradual Increase in Inattention Symptoms

MedicalResearch.com Interview with:
Samson Nivins PhD
Postdoctoral Researcher, specializing in Perinatal and Pediatric Neurology

Dr. Klingberg

Torkel Klingberg, M.D., Ph.D.
Professor of Cognitive Neuroscience at the Stockholm Brain Institute

Karolinska Institutet, Stockholm Sweden

MedicalResearch.com: What is the background for this study?

Response: In the modern era, children’s use of digital media such as watching videos, playing video games, and using social media has increased substantially, often coinciding with a decline in outdoor activities. As many school-aged children now own personal devices, particularly smartphones, it has become easier for them to spend more time on screens than intended. For example, a German survey cited in an EU briefing reported that in 2020, 27% of 8-9-year-olds and 54% of 10-11-year-olds owned a smartphone. In the U.S., ~30% of children own a smartphone by age eight, with many receiving their first device between ages 10 and 11.

With growing concerns about screen time, numerous studies have examined its potential consequences and have reported associations between higher screen use and increased ADHD symptoms. However, most of this research has been cross-sectional and has tended to combine different types of digital media such as television, video games, and social media into a single composite measure. This approach may obscure important differences, as various forms of digital media may have distinct effects on ADHD symptoms. To date, relatively few studies have examined the impact of specific types of digital media use on ADHD in a longitudinal framework, and even fewer have accounted for the heritable nature of ADHD.

To address these gaps, this U.S. longitudinal study followed children from ages 9-10 to 13-14 years. The study collected repeated measures of daily time spent on specific digital activities, including television and videos, video games, and social media platforms such as TikTok, Instagram, and Facebook. ADHD symptoms specifically inattention and hyperactivity/impulsivity were assessed using parent reports, and analyses adjusted for genetic factors and socioeconomic status.

MedicalResearch.com: What are the main findings?

Response:  We found that children with higher social media use showed a gradual increase in inattention symptoms over the four-year follow-up period, independent of genetic liability or socioeconomic status. In contrast, no such associations were observed for television/video viewing or video game use. These findings suggest that social media use may have a unique prospective link to attention difficulties during

MedicalResearch.com: What should readers take away from your report?

Response: A main takeaway from our study is how rapidly social media use increases during early adolescence. On average, time spent on social media rose from about 30 minutes per day at ages 9-10 to ~2.5 hours per day by ages 13-14, despite most platforms, such as TikTok and Facebook, requiring users to be at least 13 years old. These estimates are based on data collected between 2016 and 2022; more recent reports suggest that current usage among adolescents may exceed five hours per day.

Early adolescence is a period of increased sensitivity in the brain’s reward system. Neural circuits involved in reward processing are particularly responsive to social feedback such as likes, comments, and messages making social media a potent source of dopamine-mediated reward. At the same time, brain systems responsible for self-control and regulation are still developing. This imbalance may make it more difficult for young adolescents to disengage from social media once use becomes frequent, increasing the risk of habitual and hard-to-reduce patterns of use.

Parental supervision also plays an important role. Limited oversight of which platforms children use and how much time they spend online may allow reward-seeking behaviors to develop with few external limits. When parents are unaware of or underestimate their child’s social media use, adolescents may increasingly rely on online interactions to meet core developmental needs related to belonging, social status, and identity.

Over time, repeated dopamine-driven reinforcement from social media can shift behavior toward compulsive checking and prioritizing online engagement oversleep, schoolwork, physical activity, and in-person relationships. For some adolescents, particularly those who may already be vulnerable, this pattern may contribute to mood instability, anxiety related to online validation, and reduced enjoyment of offline activities. This is especially concerning given that many mental health conditions, including depression and anxiety disorders, commonly emerge during early adolescence.

Overall, our findings suggest that not all screen time is equal and that social media, in particular, may warrant closer attention during this sensitive developmental window. 

MedicalResearch.com: What recommendations do you have for future research as a results of this study?

Response: Future research should move beyond simple measures of total screen time and instead adopt more detailed, longitudinal approaches to better understand how social media use affects the developing brain and behavior. In particular, studies should integrate repeated behavioral and neurobiological data to examine how social media exposure influences reward-system functioning, emotion regulation, and cognitive control over time.

Research should also prioritize groups that may be especially vulnerable to the effects of social media, such as children born preterm or those with neurodevelopmental conditions. These populations may have increased sensitivity to reward-driven platforms, potentially amplifying risks related to attention, emotional regulation, or mental health.

In addition, future studies should shift focus from total daily hours of use to specific patterns of engagement. This includes behaviors such as late-night scrolling, continuous or compulsive use, and multitasking with social media during homework or school activities, which may be particularly disruptive to sleep, learning, and attention. It will also be important to distinguish between different types of social media activity. Passive behaviors, such as scrolling or consuming content, may have different effects than active engagement, such as messaging or content creation.

Finally, research should differentiate between platforms, features, and content types. Platforms like TikTok, Instagram, Snapchat, and Facebook vary substantially in their design, including the use of algorithm-driven feeds, likes, streaks, and other feedback mechanisms. Similarly, the impact of social media may depend on the type of content being consumed, such as peer interactions, appearance-focused material, news, or educational content. Disentangling these factors will be essential for identifying which aspects of social media use pose the greatest risk and which may be more benign or even beneficial.

MedicalResearch.com: Is there anything else you would like to add? Any disclosures?

Response: Australia’s under-16 social media ban, now in effect, represents a real-world experiment. It offers an opportunity to examine whether population-level restrictions on access to algorithm-driven content can help protect children’s neurocognitive development. This development raises questions for other countries about how best to address potential risks associated with early and sustained social media exposure.

There is growing international activity in this area. Countries including New Zealand, Denmark, Malaysia, and France are advancing age-verification requirements or platform-level restrictions, although implementation and enforcement vary. In the U.S., responses have included legal action rather than nationwide age-based restrictions. Notably, California and more than 40 other states have filed a joint lawsuit against Meta, focused on the potential impacts of social media platforms on children and adolescents. In the European Union, the Digital Services Act emphasizes measures such as parental controls, transparency, and platform responsibility, but does not impose a universal age-based ban.

From a public health perspective, policymakers face a narrowing window to act. Science-informed limits that prioritize brain-sensitive developmental periods particularly between ages 9 and 14 may help prevent the establishment of entrenched, reward-driven patterns of use. Similar age-based protections have long been accepted for substances such as alcohol and tobacco. Importantly, countries do not need to wait years for retrospective outcome data from Australia before considering preventive action.

For parents and caregivers, the message is practical and actionable. Even moderate daily social media exposure during critical stages of brain development may influence attention and self-regulation. Structured screen routines, device-free social time, consistent sleep schedules, and clear boundaries around nighttime use remain among the most effective protective strategies available today. Clinicians and educators can also play an important role by supporting device-level controls and school-based policies while broader legislation evolves.

Disclosures: This study was supported by the Stiftelsen Frimurare Barnhuset, Stockholm (Samson Nivins) and the Swedish Research Council (Torkel Klingberg)

Citation: Samson Nivins, Michael A. Mooney, Joel Nigg, Torkel Klingberg; Digital Media, Genetics and Risk for ADHD Symptoms in Children – A Longitudinal Study. Pediatrics Open Science 2025; https://doi.org/10.1542/pedsos.2025-000922

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Last Updated on December 22, 2025 by Marie Benz MD FAAD