School districts across the United States are adopting phone restrictions ranging from “phones away during class” to full-day, bell-to-bell bans. Nearly half of states in the U.S. as well as Washington D.C. have adopted “bell-to-bell” cellphone bans during school. The policy has bipartisan support given concerns that smartphones are distracting students from learning and contributing to a mental health crisis among teens.
But what does the science show about cellphone use in schools and the mental health effects on children and adolescents?
A 2025 peer reviewed study in The Lancet Regional Health—Europe, known as the SMART Schools study, examined more than 1,200 adolescents ages 12 to 15 across 30 different secondary schools. Students in schools with restrictive policies spent about 40 minutes less on their phones and about 32 minutes less on social media during school hours. Despite this, the researchers concluded that there was no significant difference in overall mental well-being between students in restrictive and permissive schools. The study also found no meaningful difference in total weekday or weekend phone use, meaning students simply shifted their phone use during hours away from school. This study did show that greater smartphone and social media use was associated with poorer outcomes with respect to anxiety, depression and sleep.
There are legitimate reasons for concern about excessive phone use among learners. Research consistently shows that greater social media and screen use can be associated with low self-esteem, online harassment, poor sleep and increased levels of anxiety and depression. Heavy smartphone use can also be associated adversely with academic performance. A 2020 study of more than 11,000 adolescents found that students reporting at least two hours of weekday phone use were more likely to report poor academic performance and had lower test scores in English and mathematics.
Despite the findings in the aforementioned studies, there are limitations to these research studies. A 2025 peer reviewed review in The Lancet Regional Health—Europe cautioned that much of the evidence in the literature linking smartphone use to adolescent mental health has been correlational, meaning the evidence cannot prove that increased phone usage causes adverse effects on mental health.
Removing smartphones can eliminate distraction from the classroom setting. However, there are clear benefits for phones in the hands of students. Research also shows that social media and phones can keep kids and adolescents connected fostering a sense of community, can allow adolescents to express themselves and can also promote problem-solving skills.
Thus, school phone bans are neither a cure or a mistake with respect to mental health for children and adolescents. They are one environmental intervention whose effects depend heavily upon what happens in spaces where the ban does not apply, like at home.
A feasible strategy for schools going forward could include pairing phone usage restrictions with digital-literacy education, which should focus on the benefits and drawbacks of social media use for mental health. In addition, opportunities for face-to-face socialization could foster and develop friendships and relationships. Finally, parents should also take an active role at home negotiating times their kids partake in social media and phone use. The goal should be to teach kids and adolescents when technology helps, and when it can pose a risk to health.
As the new school year begins, more states and school districts are opting to adopt restrictions on phone usage. Whether that translates into healthier, happier kids and adolescents remains an open scientific question.