We know screentime and well-being are linked — but until recently, most of the evidence has been correlational. Now, two randomized controlled trials offer causal proof that reducing smartphone engagement (whether by removing features or limiting phone usage) leads to measurable improvements in mental health and attention.

In the first study, Noah Castelo, Kostadin Kushlev, and colleagues [1] tackled what makes smartphones “smart,” their constant internet connectivity. For two weeks, participants blocked mobile internet access on their phones (calls and texts still worked). The effects were striking: significant improvements in mental health, subjective well-being, and sustained attention, driven in part by spending more time offline, sleeping better, and feeling greater self-control.

After two weeks of smartphone “internet rehab,” people’s mental health and subjective well-being improved significantly, and their ability to sustain attention jumped upward. In fact, 91% of those who underwent the internet ban improved on at least one key outcome. The magnitude of the benefits was eye-opening: on average, symptoms of anxiety and depression declined more than what’s typically seen from antidepressant medications, and participants’ attention spans improved as much as if they had reversed a decade of cognitive aging. These gains weren’t just in people’s heads – an objectively measured attention test confirmed the focus boost. Freed from constant notifications and infinite scroll, participants naturally reallocated their time: without mobile internet, they spent more hours socializing face-to-face, exercising, and being in nature. In other words, they swapped doomscrolling for hangouts and hikes. It’s causal evidence that today’s “always-online” smartphone may be undermining our well-being – and that dialing it back can reverse the damage.

Meanwhile, Christoph Pieh and team [2] tested a different approach. Instead of removing functionality, they asked some students to limit screentime to two hours a day for three weeks — an intervention that led to improvements in stress, depressive symptoms, sleep quality, and overall subjective well-being.

What’s especially fascinating is that participants in both groups — despite their different intervention approaches — ended up averaging around 2 hours/day of phone use. (That’s half the time most of us usually spend!) And it was enough to yield benefits across both studies.

Not All Digital Breaks Are Created Equal

But an interesting divergence appeared after the experimental limits were lifted. In the internet-blocking study, people didn’t fully relapse into their old screen habits once the two weeks were up. Remarkably, even weeks after getting their internet turned back on, the original intervention group was still using their phones less than before (and still felt many of the benefits). It’s as if the forced break “reset” their default behavior: having discovered life beyond the endless feed, they were less inclined to binge on it again. 

By contrast, in the time-limit study the gains proved more fragile. As soon as the three-week experiment ended, participants’ screen time returned to normal levels; at a six-week follow-up their usage and well-being metrics were back to where they started. This difference hints at a crucial insight for designing interventions: a structural change (like disabling features) may create more durable change than time, which demand willpower moment to moment — tough to sustain once external constraints disappear. 

Taken together, these two studies make an important point: how we engage with technology can meaningfully change our psychological well-being — and how products are designed definitely matters.

Designing for Disconnection

For years, the dominant strategy in tech has been to maximize engagement – more time on platform, more notifications, more features to hook users. But these studies underscore an uncomfortable truth: more is not always better for the user. In fact, intentionally designing for less screen time can directly enhance user well-being and cognitive performance. 

This doesn’t mean we expect every app maker to start blocking internet access or capping usage. It does mean we should get creative about building “well-being by design.” Think in terms of structural defaults and smart nudges that help users disconnect when they want to. For example, a product might offer an opt-in mode that automatically disables addictive feeds after a certain amount of time.

Rather than viewing reduced screen time as a threat to engagement, forward-thinking product strategists might see it as an opportunity to build trust, loyalty, and a healthier user base. After all, if your app helps people live happier, less distracted lives – even if that means they close the app sooner – isn’t that a product success in its own right?

References

1. Castelo, N., Kushlev, K., Ward, A. F., Esterman, M., & Reiner, P. B. (2025). Blocking mobile internet on smartphones improves sustained attention, mental health, and subjective well-being. PNAS Nexus, 4(2), pgaf017.

2. Pieh, C., Humer, E., Hoenigl, A., Schwab, J., Mayerhofer, D., Dale, R., & Haider, K. (2025). Smartphone screen time reduction improves mental health: A randomized controlled trial. BMC Medicine, 23, 107.