Overview
- Using data from about 10,500 U.S. youths in the ABCD cohort, researchers found that 12-year-olds with phones had roughly 1.3× higher odds of depression, 1.4× for obesity, and 1.6× for insufficient sleep versus peers without phones.
- Risk increased by about 10% for each year earlier a child received a smartphone, indicating a dose-response pattern.
- Among participants who lacked a phone at 12, those who obtained one at 13 showed worse mental health and poorer sleep that year, while obesity risk did not notably change over that interval.
- The authors emphasize the study is observational and cannot establish causation, noting measurement limits such as lifetime depression that may predate phone ownership.
- Researchers urge caregivers to consider delaying ownership, apply safeguards like parental controls and bedroom limits, and support further research and policy evaluation.