A Pediatrics study linked smartphone ownership before age 12 to higher rates of depression, obesity and sleep problems, findings that education and health experts say can undermine learning and classroom engagement. Researchers analyzed more than 10,000 participants from a longitudinal cohort and found modest but significant differences in mental and physical health outcomes tied to early phone ownership. The research arrives as dozens of states and many districts have enacted cellphone restrictions during the school day. Case studies from schools that limited phone use report sharper student engagement, fewer disciplinary incidents, and unexpected gains—Ballard High School logged a 61 percent increase in library checkouts after enforcing a ban. Principals say physical separation from phones helped reduce online peer conflict spilling into school. Policymakers and educators face tradeoffs between access and wellbeing; advocates for restrictions argue the classroom environment improves when phones are restricted, while critics caution about equity and implementation logistics.