A major US study has found that owning a smartphone before adolescence is associated with a higher likelihood of depression, obesity, and insufficient sleep among young teenagers.
The study surveyed more than 10,500 boys and girls across 21 states between 2018 and 2021. Participants were also assessed for symptoms of depression, obesity, and whether they regularly achieved the recommended nine hours of sleep per night.
According to the findings, nearly two-thirds of children owned a smartphone before the age of 12. Those early users were 31% more likely to experience depression, 40% more likely to become obese, and 62% more likely to suffer from inadequate sleep compared to peers without smartphones.
By age 13, children who had not owned a smartphone at 12 but acquired one in the following year were 57% more likely to report clinical depressive symptoms and 50% more likely to lack sufficient sleep than those who still did not have smartphones.
The researchers also found a clear trend: the younger the child at the time they received a smartphone, the higher their risk of obesity and inadequate sleep by age 13.
Dr Ran Barzilay of the University of Pennsylvania Hospital, who led the study, said the results highlight the need to consider smartphones as an important factor in adolescent health. “We should approach the decision to give a child a smartphone with caution and consider the potential effects on their wellbeing,” he said.
However, the study does not prove that smartphones directly cause these health issues. Barzilay noted: “Instead, we encourage thoughtful reflection on the health implications and a balanced view of both the positive and negative consequences.”
He added that for many teenagers, smartphones can play a constructive role by strengthening social connections, supporting learning, and providing access to information and resources that foster personal development.
