New research suggests that smartphone ownership among preteens can hurt their mental and physical health in significant ways.
Kids who own a smartphone by age 12 have higher rates of depression, obesity, and poor sleep when compared with their peers who don’t have a smartphone. That’s the conclusion of a new study published in the journal Pediatrics, which focuses specifically on smartphone use, not the effects of general screen time.
Depression and poor sleep can hurt adolescents’ ability to learn in school, said Ran Barzilay, a child and adolescent psychiatrist at Children’s Hospital of Philadelphia and the study’s lead author. The study emphasized that even modest increases in obesity, symptoms of depression, and sleep problems among adolescents can have long-term negative health effects.
“A kid who experiences mental health problems is less likely to be free to learn and study to their maximum potential at school because it affects their attention and concentration,” he said. “Lack of sleep, similarly, affects [their] ability to concentrate and to focus in class the following day.”
This research adds more support for the argument made by an increasing number of educators and policymakers that cellphone ownership is corrosive to students’ wellbeing and learning.
But those rising concerns are happening at the same time that smartphone ownership is growing among younger and younger kids. At least 43 percent of 8- to 12-year-olds have their own smartphone, according to a 2023 report from Common Sense Media.
As smartphone ownership has increased among elementary school kids and teens, policymakers and educators have focused a considerable amount of energy on student phone use in schools the past few years. At least 32 states and the District of Columbia now require school districts to ban or restrict students’ use of cellphones in schools, according to an Education Week tally.
Barzilay and his colleagues—researchers from the University of California, Berkeley, Columbia University, and Children’s Hospital of Philadelphia—analyzed data from a sample of 10,588 kids in the Adolescent Brain Cognitive Development Study, a national research consortium that is tracking a cohort of children—and the effects of common experiences on their development—into adulthood. The data on 9- to 16-year-olds was collected between 2016 and 2022.
Barzilay, who is also an assistant professor of psychiatry at the University of Pennsylvania, and his coauthors found that kids who own smartphones by age 12 are more likely to suffer from poor health outcomes than their peers who don’t.
The earlier kids got smartphones, the greater their risk of obesity and insufficient sleep by age 12, the researchers found.
The researchers also looked at kids who got smartphones between age 12 and 13 and saw similar patterns, Barzilay said.
“When we followed these kids for a year, by the end of that year when the kids were around 13, just more than half of them had gotten a smartphone,” he said. “And these kids, compared to kids who remained without a smartphone, had more mental health problems and worse sleep.”
Why educators should evaluate both the benefits and drawbacks of smartphone use
The study didn’t examine why smartphone use might lead to more symptoms of depression, obesity, and inadequate sleep. But as a child psychiatrist, Barzilay has some theories.
Kids who own smartphones are likely staying up late playing on their phones instead of sleeping; and they are spending less time engaging in physical activities, which are good for physical and mental health.
Plus, some of the harmful content preteens and teens interact with on social media and apps on their smartphones could also contribute to poor mental health, Barzilay said.
Despite all those concerns, Barzilay cautioned that conversations around the downsides of youth smartphone use need to remain nuanced and data driven. Smartphones have benefits too, he said. They facilitate connection and communication. They help students access information and parents keep tabs on their kids.
“Smartphones are not just bad, the same way that they’re not just good,” Barzilay said. “It’s part of life and we need a society to learn how to live with them and to use them in a health-promoting manner. I think for educators as well, if we give the impression that smartphones are bad, they are the mother of all evil, it’s maybe counterproductive.”