Overview
- An analysis of more than 10,000 U.S. children in the ABCD cohort found that 12-year-olds with smartphones had 31% higher odds of depression, 40% higher odds of obesity, and 62% higher odds of insufficient sleep than peers without phones.
- Each year earlier than age 12 that a child received a smartphone was linked to roughly a 10% increase in the odds of obesity and insufficient sleep at 12, with no similar per-year pattern for depression.
- Within the cohort, children who acquired a phone between ages 12 and 13 showed rapid increases in mental health problems and insufficient sleep compared with peers who still had no device.
- Authors controlled for income, parental education, puberty, parental monitoring and other devices, but the observational design cannot establish causation and lacked data on how or what kids used on phones.
- Ownership is already common by age 12 in the U.S., yet experts advise delaying when possible, keeping phones out of bedrooms and using parental controls, while a reader poll found 53% prefer first phones at 14 or older.