Parents hear regularly that too much screen time harms children, but two studies published in September 2026 suggest the picture is more complicated than a daily hour count. One looks at screen use and development across dozens of reviews, and the other looks at personal smartphone ownership and eating disorder symptoms in early adolescence. Both point toward what children do on screens, what those screens replace and when children get their own devices.
What the broad review found
The first study, published in JAMA Pediatrics, is an umbrella review. Instead of collecting new data, it pooled findings from 23 meta-analyses, which themselves combine individual studies. Together they covered more than 2.8 million children and teens in 64 countries. Greater screen-based media use was associated with lower overall academic achievement, lower language skills, more emotional problems, more internalizing problems such as anxiety, depression and withdrawal, more externalizing behavior problems such as acting out or breaking rules, and more peer problems. Social media use was specifically linked to more internalizing problems.
The associations were generally small. One of the study's authors told CNN that "small does not mean meaningless," and the researchers highlighted the links to emotional and peer problems as the more concerning findings. The strength of the associations also varied by type of screen use and by a child's age.
Smartphones and eating disorder symptoms
The second study, published in JAMA Network Open, drew on 8,957 U.S. adolescents in the Adolescent Brain Cognitive Development (ABCD) Study, nearly 70 percent of whom had their own smartphone at age 12. Researchers tracked binge eating, behaviors used to prevent weight gain, worry about weight gain and tying self-worth to weight.
At age 12, children who owned a smartphone were more likely to report binge eating, tying self-worth to weight and having at least one eating disorder symptom. Two years later, they were also more likely to report binge eating, weight-prevention behaviors, self-worth tied to weight and at least one symptom. The study found an association, not a cause. Researchers do not yet know the mechanism, but they point to several possibilities: exposure to appearance-focused or idealized images, comparison with others online, content promoting disordered eating, disrupted sleep and routines, and the private, personalized nature of phone use.
Why early adolescence matters
Early adolescence is already a period of increased risk for eating disorders. Children at this stage grow more attentive to peer opinion, appearance and social acceptance, and they may have more trouble regulating emotions or using effective coping strategies. A personal phone can widen their exposure to online content and social pressure during those years. Earlier analyses from the same data set also linked each additional hour of screen time and social media use to higher odds of compensatory behaviors, binge eating symptoms and weight-related self-worth.
What parents can look at
- Content and activity: Watching an educational video, playing with friends and scrolling appearance-focused feeds are different experiences.
- What screens replace: Screen time can crowd out sleep, physical activity, schoolwork, hobbies and family time.
- Timing of a personal device: The age at which a child gets a smartphone is worth considering, though the research does not show that owning one at 12 causes harm.
- Changes in the child: Shifts in mood, sleep, eating, grades or friendships are reasons to check in. If concerns persist, a pediatrician can advise on whether further evaluation is needed.
Neither study names a safe or unsafe number of hours for every child, and neither shows that screens or smartphones directly cause the outcomes measured. What the research offers is a fuller set of questions to ask: what a child is doing and seeing, what that use is displacing, and when personal devices enter a child's day. For many families, those questions may tell them more than a tally of minutes.