As Americans scramble to respond to rising rates of suicidal behaviour among youth, many policymakers have locked in on an alarming metric: the number of hours a day that American children spend glued to a glowing screen.

But a study published June 18 in the medical journal JAMA, which followed more than 4,000 children across the US, arrived at a surprising conclusion: Longer screen time at age 10 was not associated with higher rates of suicidal behaviour four years later.

Instead, the authors found, the children at higher risk for suicidal behaviours were those who told researchers their use of technology had become “addictive”  – that they had trouble putting it down or felt the need to use it more and more. Some children exhibited addictive behaviour even if their screen time was relatively low, they said.

The researchers found addictive behaviour to be very common among children – especially in their use of mobile phones, where nearly half had high addictive use. By age 14, children with high or increasing addictive behaviour were two to three times as likely as other children to have thoughts of suicide or to harm themselves, the study found.

“This is the first study to identify that addictive use is important and is actually the root cause, instead of time,” said Yunyu Xiao, an assistant professor of psychiatry and population health sciences at Weill Cornell Medical College and the study’s lead author.

Addictive behaviour may be more difficult to control during childhood, before the prefrontal cortex, which acts as a brake on impulsivity, is fully developed.

Xiao said interventions should focus on the child’s addictive behaviour, which is typically treated with cognitive behavioural psychotherapy, rather than simply limiting access to screens.

“If there are early warnings, then for parents, it’s important to seek professional help for children with such addictions,” she said. “We do not know if just taking away their phone will help. Sometimes it can create some conflict in the family, and that is even worse.”

The study analysed changes in screen use among 4,285 children beginning around age 10, regularly screening them for compulsive use, difficulty disengaging and distress when not given access.

At 14, when the subjects were assessed for suicidal behaviour and mental health status, 5.1% of the participants had showed suicidal behaviour, such as attempted suicide or preparation for an attempt, and 17.9% had experienced suicidal ideation.

Because of its design, the study did not establish that addictive use caused suicidal behaviours at age 14, but it was able to show that a prolonged trajectory of addictive use preceded the mental health problems, Xiao said.

The focus on addictive behaviour has important policy implications, shifting more responsibility onto the technology companies that design devices and social media platforms, said Mitch Prinstein, chief science officer at the American Psychological Association.

Policymakers can address addiction by requiring technology companies to introduce “age-appropriate design” that limits features adolescents find difficult to resist, he said. The United Kingdom introduced a code of this kind in 2020. “We just don’t do that here,” he said. “We have baked addictive use into the design of the product.”

Debates about screen time, by contrast, tend to put the onus on parents to limit their children’s use of the platforms, a task that can be especially difficult for single-parent or lower-income families, he said.

“We are talking about something that’s just not feasible for some people who rely on that device to calm their kids down for a few minutes to give them a moment to fold the laundry and get dinner ready or go off to a second job,” he said.

The new study found higher levels of addictive use of social media, video games and mobile phones among Black and Hispanic adolescents, and among youths from households with annual incomes less than US$75,000 (RM318,787), unmarried parents and parents without a college education.

For nearly half of the children in the study, addictive phone use was consistently high from age 11; another 25% began with low addictive use, which increased steeply.

For that last group, “the risk of suicidal behaviour clearly increased, to a doubling of the levels,” Xiao said. “So if we do not measure them repetitively, we could miss this group when they are growing up.”

The new study is unlikely to quiet worries about screen time, which has become a major public health issue. US teens spend an average of 4.8 hours per day on social media platforms like YouTube, TikTok and Instagram, Gallup found in 2023, the most recent year for which data is available.

In his 2024 book The Anxious Generation, Jonathan Haidt, a social psychologist, identified the appearance of the smartphones as a key inflection point, after which youth mental health in the United States began to deteriorate. Since then, legislators in many states have crafted laws limiting social media use or screen time, especially during school hours.

Many scientists who study the relationship between social media and mental health say it is premature to issue blanket warnings, arguing that the research so far has told a mixed story of harm and benefit, and what seems to matter more is what they are doing online.

“We have known for over a decade now that screen time is a flawed measure, but we continue to tally time spent on screens instead of asking how young people are spending their time online and why they want to be there,” said Candice L. Odgers, a professor of psychological science in informatics at the University of California, Irvine.

Dr Jason Nagata, who has published studies on screen time but was not involved in the new JAMA study, said the data points to the limitations of screen time as a predictive measure. But he said screen time remains useful, because it’s easier to measure, and it crowds out important activities such as sleep, exercise and face-to-face socialising.

Nagata and his team found a link between higher screen time at age 9 and suicidal behaviours two years later, with each additional hour of screen time associated with 1.09 higher odds of mental health problems. Another follow-up study found more screen time was linked to a range of mental health symptoms two years later, though the effect sizes were small.

Nagata, an associate professor of paediatrics at the University of California, San Francisco, said the difference may be that Xiao’s team measured screen time at age 10 and only took mental health measurements four years later. “Four years is a long time,” he said. “I’m not surprised that some associations faded over that time.”

Jean Twenge, a psychologist who was not involved in the new study, came to a similar conclusion. “Kids’ screen time at 10 likely bears little resemblance to their screen time at age 14,” said Twenge, the author of 10 Rules For Raising Kids In A High-Tech World.

She said screen time and addictive use are both important, and her recommendations to control them are the same: Keep children off social media until they are 15, and delay giving them internet-enabled phones for as long as possible. –  ©2025 The New York Times Company

Those suffering from problems can reach out to the Mental Health Psychosocial Support Service at or ; Talian Kasih at 15999 or on WhatsApp; Jakim’s (Department of Islamic Development Malaysia) family, social and community care centre at on WhatsApp; and Befrienders Kuala Lumpur at or go to befrienders.org.my/centre-in-malaysia for a full list of numbers nationwide and operating hours, or email sam@befrienders.org.my.

This article originally appeared in The New York Times.