A new American study published on September 25, 2026, in JAMA Network Open has reignited the debate about the appropriate age for first smartphone ownership. The research examined the link between owning a smartphone at age 12 and the emergence of symptoms of eating disorders in adolescents. The study analyzed data from 8,957 young people who were part of the large American ABCD Study, conducted in 21 sites across the United States. Nearly 70 percent of the participants already owned a smartphone at age 12. Scientists checked whether these adolescents exhibited more signs suggestive of eating disorder behaviors, such as episodes of food compulsions, behaviors aimed at avoiding weight gain, excessive worry about weight, or self-esteem strongly linked to weight. The results showed a clear association: at age 12, adolescents who owned a smartphone more frequently reported episodes of food compulsions, self-esteem linked to weight, and at least one symptom of an eating disorder. Two years later, at age 14, the link persisted: young people who had smartphones at age 12 had a higher risk of reporting food compulsions, compensatory behaviors to avoid gaining weight, or personal self-esteem dependent on weight. Among adolescents who owned a smartphone at age 12, nearly a quarter reported at least one symptom of an eating disorder at age 14. The authors also note that girls may be particularly concerned about weight-related worries. The study does not claim that a smartphone directly causes eating disorders. It highlights an association, not a cause-and-effect relationship. However, researchers suggest several possibilities. A personal phone gives adolescents more frequent, private, and often less supervised access to digital content. At this age, young people are particularly sensitive to others' opinions, social comparisons, and physical norms. Social media can expose adolescents to idealized body images, content focused on appearance, or communities promoting dangerous eating practices. The authors also mention the possible role of sleep. Smartphone use in the evening can disrupt sleep, which can weaken emotional and appetite regulation. For parents, this study does not mean that they should panic when a child asks for a phone. It rather invites them to consider when the smartphone becomes personal, as well as the rules that accompany it. Researchers recommend helping families set age-appropriate limits, supervise usage, and talk to adolescents about what they see online. They also suggest that doctors ask young people about their smartphone and social media use when evaluating their mental health or body image.