The early 2000s marked a technological turning point for much of the world as broadband internet rapidly expanded, promising greater connectivity, access to information, and economic opportunity.
While the benefits of internet access are widely acknowledged, concerns have emerged about its unintended side effects, especially for vulnerable young people navigating critical stages of emotional and psychological development.
New research by Columbia Business School Professor Dante Donati; University of Singapore Professor Ruben Durante; University of Vienna Professor Dijana Zejcirovic; and Tor Vergata University Professor Francesco Sobbrio provides clear evidence that high-speed internet access during adolescence can have serious downsides. By linking hospital records with municipal broadband rollout data, the researchers found a significant rise in mental health diagnoses, particularly among people exposed at younger ages.
The findings raise urgent questions about how digital infrastructure shapes not only economic opportunity, but also the well-being of the next generation.
How the Research Was Done
To isolate the internet’s impact on youth mental health, Donati and his co-researchers linked two uniquely comprehensive data sources: Italy’s full hospital discharge records from 2001–2013 and detailed municipal-level data on broadband (ADSL) and mobile (3G) internet rollout.
The study focused on individuals born between 1974 and 1995, comparing mental health outcomes for different birth cohorts.
Similar to most countries, the rollout of broadband internet in Italy unfolded unevenly across the country, reaching some communities faster than others. This staggered introduction helps assess the impact of the internet on mental health, comparing areas with more and less connectivity. However, municipalities that got broadband earlier might also differ in other ways, such as being wealthier or more urban, which could influence mental health independently. To get around this, the researchers took advantage of a technical detail: a town’s distance from the nearest central telecom switch, known as an Urban Grouping Station (UGS), played a big role in when it received broadband. Since these stations were built long before the internet era, their location was unrelated to mental health trends. That allowed the researchers to treat the broadband rollout as a natural experiment, pinpointing its actual effects on young people’s mental health.
What the Researchers Found
The internet didn’t affect everyone’s mental health in the same way. For people who were already adults when broadband arrived (those born between 1974 and 1984), the researchers found no meaningful changes in hospitalizations for mental health disorders. However, for younger people—those born between 1985 and 1995, who were in their teens or early twenties during the rollout—the story was different.
In towns with full broadband access, young people were more than 20% more likely to be hospitalized for at least one mental health issue in a given year, compared to areas with no connectivity. These included diagnoses for depression, anxiety, drug and alcohol abuse, and personality disorders. Among young women in particular, there was also a noticeable rise in hospitalizations related to eating and sleep disorders.
The researchers looked closely at whether this could simply be a case of better awareness or easier access to mental health services. But the data showed increases in more severe cases too, such as self-harm and involuntary psychiatric hospitalizations, suggesting a deeper problem than just improved diagnosis or reporting.
The team saw the same pattern when they analyzed mobile internet access via 3G networks. This points to a broader issue tied to fast, always-on internet rather than any single device or platform.
Why the Research Matters
The study offers some of the strongest causal evidence to date on the mental health risks of internet exposure during adolescence.
Unlike many prior studies that rely on self-reported well-being, Donati and co-authors used hospital-diagnosed mental health cases, covering the entire country and controlling for urbanization, demographics, and health care supply.
The findings are especially timely as debates over the role of technology in young people’s lives gain urgency worldwide. Platforms like TikTok, for instance, have come under increasing scrutiny for their impact on teen well-being. In response to concerns about body image and anxiety, the platform recently began restricting the use of appearance-altering filters for users under 18. Several U.S. states have filed lawsuits against TikTok and other social media companies, alleging that their algorithms contribute to addictive behavior and deteriorating mental health among minors. Some lawmakers have even proposed banning access to such platforms for children under 13.
While the study focuses on the early 2000s, before the rise of modern social media, it highlights that the mental health effects of digital access go beyond individual platforms. Fast, always-on internet changes how young people spend their time, often at the expense of in-person interaction, sleep, and emotional resilience. Adolescence emerges as a uniquely vulnerable period because the impact is most substantial for those exposed at younger ages.
As policymakers weigh the tradeoffs of expanding digital infrastructure, this research adds urgency to calls for protective measures: digital literacy programs, age-sensitive design standards, and parental oversight tools. While connectivity brings opportunity, its costs, especially for vulnerable youth, cannot be ignored.
