ABCD Cohort Links Age-12 Smartphone Ownership to 61% Higher Binge-Eating Odds and Doubled Weight-Self-Worth Linkage by Age 14

Researchers used parent-reported smartphone ownership and age-12 and age-14 computerized psychiatric interviews within the nationally diverse ABCD sample. At age 12, 69.5% already owned phones; owners showed markedly elevated eating-disorder symptoms both concurrently and prospectively, with nearly one in four reporting at least one symptom by age 14. The findings align with earlier observational work on social-media exposure and body-image disturbance yet extend them by isolating device ownership itself. Algorithmic feeds deliver continuous thin-ideal and pro-disorder content during puberty, when self-regulation is immature and peer approval seeking peaks; parents systematically under-report these internalized symptoms. Next steps require randomized restriction trials and objective screen-time logging to test causality and identify dose thresholds. Without such data, policy on minimum smartphone age remains guided by associations rather than intervention evidence.