The New York Times is heralding a new study that correlates the age of smartphone adoption with negative health outcomes for children. The study was published in the December issue of the journal Pediatrics.

The study relies on analysis of data collected by the Adolescent Brain Cognitive Development study (ABCD Study), the largest long-term study of brain development in the U.S.  The study involved 10,588 participants, all of whom were “reported by caregivers, with depression, obesity, and insufficient sleep at age 12 years.”

The study found:

• At age 12 years, compared with not owning a smartphone, smartphone ownership was associated with a higher risk for depression, obesity, and insufficient sleep.

• A younger age of smartphone acquisition was associated with obesity and insufficient sleep.

• Smartphone ownership was associated with depression, obesity, and insufficient sleep in early adolescence.

Readers of AddictionNews will appreciate the use of a video abstract (see below) by Pediatrics in which lead author Ran Barzilay, M.D., Ph.D., from Children’s Hospital of Philadelphia and the psych department at the University of Pennsylvania Perelman School of Medicine, talks through the study.

One finding is a survey of the prevalence of smartphone ownership among youth. A 2024 Pew Research study showed 95% of teens aged 13-17 own a smartphone. That’s very close to universal adoption.

More than half of U.S. children aged 11 and 12 have smartphones. Pew pegs the number at 57%. For 8-10-year-olds, 29% have a smartphone. Researchers found the median age for first getting a smartphone in the U.S. is 11, followed closely by age 10, then age 12.

The researchers then looked at the association between early smartphone adoption and health outcomes at age 12 and at age 13.  They concluded:

“Among those who had a smartphone, the earlier age they had it, the worse their health outcomes,” says Dr. Barzilay in the video. For those who did not have a smartphone at age 12, but received one in the following year, their outcomes were already worse by age 13, with “poorer mental health and sleep quality.”

Dr. Barzilay admits to The New York Times that he has three children, and he gave two of them smartphones before the age of 12. He is going to try and hold off with his nine-year-old, he says.

Leaked documents from the ongoing court cases against the social media companies over smartphone addiction show that the companies were aware of the negative health impacts of their products on children, but brought them to market regardless. An internal chat from developers at Instagram referred to the service as “a drug” and to themselves as “pushers.”

Snapchat executives applauded children getting “Snapchat addiction.” According to CNN, an internal TikTok report included the revelation that “minors do not have executive mental function to control their screen time.” And YouTube was made aware that increasing daily usage did not align with “improving digital wellbeing.”

The tech companies are being accused of “deliberately embedding design features into their platforms” that have contributed to a “mental health crisis” costing school districts millions of dollars to abate.

The current study does not show a causation between smartphone adoption and poor mental health, just an association. There are many things going on in kids’ lives at that age that could contribute to poor mental health besides smartphones. 

However, it’s important to realize that these devices can impact sleep and mood and school performance — in fact, they’ve been designed for it — so it’s best to limit access to smartphones during sleeping hours and limit the phone’s access to social media as much as possible.

Written by Steve O’Keefe. First published December 4, 2025.

Sources:

“A Smartphone Before Age 12 Could Carry Health Risks, Study Says,” The New York Times, December 1, 2025.

“Smartphone Ownership, Age of Smartphone Acquisition, and Health Outcomes in Early Adolescence Available to Purchase,” Pediatrics, December 1, 2025.

“Teens, Social Media and Technology 2024,” Pew Research Center, December 12, 2024.

“Lawsuit alleges social media giants buried their own research on teen mental health harms,” CNN, November 26, 2025.

Image Copyright: patrykkosmider.