HMN 2026: How Age limits alone won’t fix smartphone risks

Researchers at Children’s Hospital of Philadelphia (CHOP), in collaboration with the University of California, Berkeley, and the University of Pennsylvania Perelman School of Medicine, found that a year after receiving their first smartphone at age 13, teens at 14 who spent significant time on their phones were more likely to experience depression, obesity and insufficient sleep. The study is published in JAMA Pediatrics.

Ran Barzilay, MD, Ph.D., the study’s senior author and a child psychiatrist with the Youth Suicide Prevention, Intervention and Research Center at CHOP, and Ziv Bren, MD, the study’s lead author and a pediatrician and postdoctoral research fellow at CHOP, expanded on Barzilay’s previous smartphone research. Last year, Barzilay and his collaborators reported that teens from the Adolescent Brain Cognitive Development study (ABCD) who acquired their first smartphone by age 12 were at greater risk of mental health issues and insufficient sleep than those who remained “smartphone-free” at age 13.

In this new study, Barzilay and his team followed the “smartphone-free” cohort from age 13 to 14. The researchers looked at whether getting a smartphone around age 13 affected depression, obesity or sleep one year later.

Of the 1,959 teens studied, 1,230 obtained a smartphone between ages 13 and 14, while 729 did not. Compared with those who did not acquire a smartphone, those who did acquire one at age 13 were at risk for insufficient sleep by age 14.

Researchers found that simply acquiring a smartphone at age 13 was not associated with depression at age 14, in contrast to first acquiring a smartphone at age 12, which was linked to adverse mental health a year later. The research suggests that by age 13, teens may be more emotionally ready to receive their first smartphone without it automatically harming their mental health.

However, when examining the intensity of smartphone use, the researchers found that the duration of time on a smartphone and nighttime access are key factors that contribute to overall wellness. For children who had smartphones by age 14, using them for more than 5 hours a day was linked to more than twice the chance of depression and obesity, and double the chance of not getting enough sleep, compared with using them 2 hours or less a day. The study did not examine which specific phone activities (like gaming or social media) might be harmful.

“A simple habit appeared to reduce adverse outcomes. Kids who kept their smartphone devices outside the bedroom at night were less likely to report insufficient sleep, suggesting that removing them from bedrooms makes an impact on teen wellness,” Barzilay said.

“When considering the findings of this paper alongside our previous work, we can cautiously say that smartphone acquisition at age 13 appears safer than at or before age 12. However, even at age 13, our findings provide evidence informing parents and clinicians that it’s important to introduce a smartphone with clear rules and supervision. We encourage families to set daily limits on smartphone use and remove them from their children’s bedrooms at night.”

Barzilay said the team will continue to evolve its research with an eye toward better understanding the impact of smartphone use, and specific types of use, on children’s and teens’ wellness.

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