Hooked on Screens: What it’s Doing to Our Brains
By Raquel Loga
As smartphones and screens become an integral part of everyday life across all age groups, the need to understand how this technology affects our brain health is increasingly urgent. A wide body of research points to potential adverse effects of excessive screen time on mental health in general, and cognitive health specifically. As Generation Z, the first generation of true digital natives, reaches the workforce, we have the opportunity to see how growing up with a consistent screen presence impacts adult mental health, and how we can counteract any negative effects in the future.
Why is the world more screen-centric?
To appreciate the impacts of screen usage on our cognitive development and collective well-being, we must first understand the factors driving its proliferation in modern-day society. To give a quick overview of the rapid rise in screen use, a cross-sectional study of Swiss students’ digital habits showed that smartphone usage rose from 23% in 2012 to just over 72% by 2020 (Mora-Monteros et al., 2023).
However, most experts agree that it was the COVID-19 era that truly transformed how we interact with the digital world. As researchers explain, “Screen time during COVID-19…further increased as a result of public health measures enforced by governments to curb the pandemic” (Pandya & Lodha, 2021). Laptops and smartphones became the primary source of entertainment and social connection, as well as essential tools for work and study. Pandya and Lodha continue: “With the global societies under lockdown, the only medium to stay socio-emotionally connected was the digital one.”
Today, the global pandemic is mostly behind us, but our reliance on digital devices for socialization remains. Screens have become much more than entertainment tools; they are intrinsically intertwined with almost every aspect of daily life, including work, communication, education, healthcare and finance. However, it begs the question: how has all this impacted our cognitive abilities and mental health?
Screens and cognition in young people
Multiple studies have shown that elevated screen time has important ramifications for the development of young brains. Since the early 2000s, a plethora of research has been conducted in this critical area, revealing both positive and negative effects. On the positive side, these devices make knowledge more accessible (Pew Research Center, 2022) and can encourage collaboration, engagement and motivation among students (Thomas et al., 2013).
However, they have also been linked to several adverse effects, including increased distraction, compromised self-regulation and reduced attention span, ultimately reducing cognitive capacity, or the ability to process information and perform mental tasks (Ward et al., 2017). “The mere presence of one’s smartphone may impose a 'brain drain' as limited-capacity attentional resources are recruited to inhibit automatic attention to one’s phone, and are thus unavailable for engaging with the task at hand,” the research team notes.
This split-focus phenomenon could explain why metrics like math, reading comprehension and writing are on the decline, according to reputable sources like the National Center for Education Statistics in the US. Reading on-screen just does not promote brain connectivity in the regions related to language and cognitive control as reading paper books does (Horowitz-Kraus & Hutton, 2017), a fact that raises more questions about the future of learning and critical thinking in an increasingly digital world.
What about adult brains?
Are these impacts present as we age, too? The short answer is yes. With screens and advancements such as artificial intelligence and virtual and augmented reality taking hold, researchers have been able to conduct experiments that map out exactly what these technologies do to the brain in real time.
In a scoping review of theoretical and empirical studies, Neophytou et al. (2021) found evidence linking the overuse of smartphones with lower self-esteem, addictions, delayed learning and knowledge acquisition, and increased incidences of cognitive, emotional and behavioral challenges in young adults. Additionally, there is a higher chance it might lead to early-onset dementia later in life due to thinning of the cerebral cortex between the ages of 18 and 25.
Meanwhile, Xu et al. (2024) conducted a large-scale, prospective cohort study following more than 400,000 respondents over 12.6 years. Researchers used MRI scans to observe brain activity and structure in adults. The results showed that those who watched TV for five hours or more every day had an increased risk of experiencing stroke, dementia or Parkinson’s disease compared with those who watched less than an hour a day. More TV time was also linked to a lower volume of gray matter in the brain.
Other studies link excessive smartphone use to altered gray matter volume in adults, impairing concentration, memory retention, recall, social functioning, and general self-care and well-being. These factors are linked to neurodegeneration in adulthood, leading to early-onset dementia and other conditions (Manwell et al., 2022). A 2024 study found a correlation between late-night phone use and reduced cognitive scores in information speed processing, working memory, calculation, and attention (Shalash et al., 2024).
Can reducing screen time improve mental and cognitive health?
In order to determine whether controlling screen time can yield tangible results for our well-being, researchers conducted a randomized controlled trial to explore the effects of smartphone use reduction on mental health in young adults. Participants who limited their daily screen time to under two hours for just three weeks reported significant improvements in key mental health markers, including reduced stress and depressive symptoms, better sleep quality and higher overall well-being (Pieh et al., 2025).
That said, the study also found that old habits die hard. Once the three-week intervention ended, participants’ screen time crept back toward previous levels. This underlines a core challenge of our digital era: even when we know screens can harm us, it’s still hard to put them down.
Part of the problem may be how digital devices shape our behavior and brain function. “It’s not how long we’re using screens that really matters; it’s how we’re using them and what’s happening in our brains in response,” says pediatrician Michael Rich of Boston Children’s Hospital (Ruder, 2019). Devices that are designed to entertain, distract or deliver constant feedback can interfere with everything from sleep to memory consolidation to creativity. As Rich puts it, “Fire was a great discovery to cook our food, but we had to learn it could hurt and kill as well.” The same may be true of our screens.
In short, using screens more intentionally, and less reflexively, may be a key strategy for protecting cognitive health. Small, consistent changes, like limiting smartphone use in the evening or creating screen-free zones, can go a long way.
Nurturing cognitive health
While easier said than done, we can only progress by taking consistent, measurable action.
On the policy front, regulators can develop measures encouraging individuals and institutions to reduce screen time, reintegrate physical books and print media, and take up more physical activities to boost cognition.
As individuals, we can take a proactive approach to our media consumption habits. For instance, cutting recreational TV can significantly improve cognitive function in the short- and long-term.
Designate “screen-free” periods while eating or before bed to avoid overstimulation, reduce stress, improve digestion and experience better sleep for longer.
Finally, replace passive screen time, like flipping through TV channels or endlessly scrolling through social media feeds, with healthier pastimes that anchor attention in the here and now, such as exercise, meditative breathing techniques and social connection.
While this list is far from exhaustive, it offers a practical starting point for improving cognitive health and overall well-being. By experimenting with different combinations, we can create a framework for navigating the contemporary digital world to maximum positive effect. After all, a healthy, stress-free brain is the key to working better, achieving more and reaching higher levels of happiness, at school, work, home and beyond.
Sources
Horowitz-Kraus, T. & Hutton, J. S. (2017). Brain connectivity in children is increased by the time they spend reading books and decreased by the length of exposure to screen-based media. Acta Paediatrica 107 (4), 685–693. https://doi.org/10.1111/apa.14176
Manwell, L., Tadrod, M. C., Ciccarelli, T. M. & Eikelboom, R. (2022). Digital dementia in the internet generation: Excessive screen time during brain development will increase the risk of Alzheimer's disease and related dementias in adulthood. Journal of Integrative Neuroscience 21 (1), 28. https://doi.org/10.31083/j.jin2101028
Mora-Monteros, M., Suris, J., Chok, L., Siwiak, A., Stadelmann, S. & Barrense-Dias, Y. (2023). Evolution of screen use among youth between 2012 and 2020 in Switzerland. Archives de Pédiatrie 30 (8), 563–566. https://doi.org/10.1016/j.arcped.2023.09.001
National Center for Education Statistics. (n.d.). The Nation’s Report Card. https://www.nationsreportcard.gov/
Neophytou, E. Manwell, L. A. & Eikelboom, R. (2021) Effects of excessive screen time on neurodevelopment, learning, memory, mental health, and neurodegeneration: a scoping review. International Journal of Mental Health and Addiction 19, 724–744. https://doi.org/10.1007/s11469-019-00182-2
Pandya, A. & Lodha, P. (2021). Social connectedness, excessive screen time during COVID-19 and mental health: A review of current evidence. Frontiers in Human Dynamics 3. https://doi.org/10.3389/fhumd.2021.684137
Pew Research Center (2022). Teens, Social Media and Technology 2022. https://www.jstor.org/stable/pdf/resrep63507.pdf?acceptTC=true&coverpage=false&addFooter=false