Bold claim: Owning a smartphone by age 12 is linked to real health risks for kids—and the connection is more than just a side note. As we learn more about how smartphones shape childhood, a new study focusing on tweens on the brink of adolescence adds some challenging findings.
U.S. researchers found that 12-year-olds who have their own phone show higher odds of depression, obesity, and insufficient sleep compared with peers who do not have a device. Since smartphones have only become commonplace in the last two decades, studies like this help tease apart which effects are tied to device use and which may be part of broader development.
According to Ran Barzilay, a child and adolescent psychiatrist at the Children’s Hospital of Philadelphia, these results suggest smartphones deserve careful consideration when deciding whether a child should have one. He emphasizes that the decision should account for potential impacts on health and daily life.
Related science indicates that screen time, especially near bedtime, can be linked to sleep problems, and other research has explored how screen use intersects with mood and behavior. The current study analyzed data from 10,588 young people enrolled in a long-running study on adolescent brain development. It captures a snapshot of health at age 12 and tracks changes over the following year as some participants receive phones while others do not.
The researchers adjusted for demographic and socioeconomic factors and found that at age 12, about 6.5% of those with phones had a depression diagnosis, compared with about 4.5% of those without. The gap appears modest on a percentage basis, but it remains meaningful in statistical terms.
On the obesity front, roughly 18% of phone owners were classified as obese versus 12% of non-owners at age 12. Sleep insufficiency followed a similar pattern: 47% of phone users reported sleeping less than nine hours per night, compared with 31% of peers who did not own a phone.
By age 13, youths who had a phone were more likely to report mental health concerns (including depression) and insufficient sleep than those without a device. There wasn’t a clear difference in obesity risk over that additional year, though.
The researchers acknowledge that phones can offer benefits—other studies have suggested screen time isn’t universally bad for teen mental health—and they call for more efforts to ensure responsible use of these devices.
Barzilay notes that smartphones can strengthen social connections, support learning, and provide access to information and resources that promote growth. At the same time, families may see a phone as essential for safety or staying in touch.
Several nuances shape the data. For instance, depression was measured as any depressive episode up to the present, so in some cases it may have begun before the child received a phone.
As an observational study, it cannot establish cause and effect. Still, the strength of the associations and the observed shifts between ages 12 and 13 as some children gained phones while others did not warrant deeper investigation.
The findings align with what is known about adults: smartphones can contribute to stress, increase distraction, and alter brain activity. Future research aims to explore how different levels of screen time and app types influence outcomes, whether effects persist into later adolescence, and what countermeasures could mitigate risks.
Barzilay emphasizes the importance of giving young people opportunities to disconnect, encouraging physical activity that supports both physical health and mental well-being. This aligns with a broader view that balanced use of technology is key.
The study has been published in Pediatrics (DOI: 10.1542/peds.2025-072941).
Would you like to see this rewritten in a more conversational style with practical tips for parents, such as setting limits, establishing device-free times, and model behaviors for healthier smartphone use?
