Mental health problems and obesity are just some of the possible side effects of early smartphone use. Researchers urge parents to think about possible consequences before giving their children a smartphone and to set clear guidelines beforehand.
A new study from the University of California, Berkeley, and New York City’s Columbia University has looked at the health data of 10,588 adolescents, 6,739 of whom owned a smartphone, in order to determine the health effects of smartphone use on children aged 12 or younger. The data used were part of the Adolescent Brain Cognitive Development Study, conducted between 2018 and 2020, considered to be the largest long-term study of brain development and child health in the US.
Depression, obesity, and insufficient sleep
According to the new research, which was published in the peer-reviewed journal Pediatrics, smartphone use before the age of 12 created an increased risk of depression, obesity, and insufficient sleep. In their turn, the three conditions are risk factors for heart disease, cancer, and diabetes.
While the researchers want to look into more specific parts of smartphone use and their consequences on children’s health, the first phase of their study already urges people to reflect on the subject. In the past, studies have proven that phone use can be of great importance as far as the social development of children is concerned, and in case of emergencies. However, guidance is needed.
“We’re not claiming smartphones are detrimental to all adolescents’ health; rather, we advocate for thoughtful consideration of the health implications, balancing both positive and negative consequences. Most probably, all teens will eventually have a smartphone. Once this happens, it is advisable to monitor what our children do on their phones, ensuring they’re not exposed to inappropriate content and that smartphones don’t disrupt sleep”, Ran Barzilay, a child psychiatrist involved in the study, said in a statement.
Moreover, in their conclusion, the scientists advocate for the development of a public policy that protects young smartphone users from possible harmful content online, a subject that is gaining attention globally.
While the Adolescent Brain Cognitive Development Study might be one of the most comprehensive Brain development studies up to date, it is important to note that smartphone use has evolved since the data were gathered. A Pew Research Center survey from October 2025 has shown that over 60% of kids aged between 11 and 12 currently own a smartphone, a percentage that has grown since 2018-2020. Of those aged eight or younger, 51% own a smartphone in 2025, according to Common Sense Media, compared to 45% in 2017.
The overall impact of smartphone use among children on our society might thus be even bigger than the study by the University of California, Berkeley, and New York City’s Columbia University suggests.
