Using smartphones at bedtime can be a dangerous habit for teens, tweens, and adolescents. (© De Visu - stock.adobe.com)
In A Nutshell
- ChatGPT surprised researchers by solving Plato’s ancient square puzzle with algebra instead of geometry.
- The AI resisted wrong suggestions, explaining why certain shortcuts wouldn’t work.
- With prompts, it revealed both recall and problem-solving behaviors, resembling student learning.
- Researchers described a “Chat’s Zone of Proximal Development,” where guidance helps the AI go further.
- The study is exploratory, based on one conversation, but raises new questions about AI in education.
SAN FRANCISCO — Turning 13 is a milestone most kids look forward to, but it carries a challenging twist that parents might not see coming. New research following more than 10,000 adolescents reveals that this birthday often brings a sharp change in bedtime screen habits that winds up cutting into the sleep teens need most.
The study, part of the Adolescent Brain Cognitive Development (ABCD) project, shows that once kids hit the age when social media platforms officially allow them to sign up, their nighttime routines begin to shift. With access to apps like Instagram, TikTok, and Snapchat, bedtime can quickly become another hour of scrolling, streaming, and messaging instead of winding down for rest.
Researchers found that just over 70% of 12- and 13-year-olds already had a device in their bedroom. As kids aged within that short span, they became more likely to watch videos, check social media, or text while lying in bed. These habits were not harmless background activity. More screen use at bedtime was linked to shorter sleep and more disturbances.
As the team wrote in Sleep Health: Journal of the National Sleep Foundation, “We anticipate bedtime screen use, particularly social media, to increase around age 13, given that the minimum social media age requirement is 13 years.”
Teens Being Woken Up By Overnight Texts
Dr. Jason Nagata of UC San Francisco, the study’s lead author, and his team looked at what young teens actually did in bed with their devices. The list covered watching videos, gaming, listening to music, texting, social media, browsing, and even schoolwork.
The numbers paint a clear picture:
- About 61% watched videos in bed at least once in the past week.
- Roughly 44% checked social media while in bed.
- Just over half listened to music before falling asleep.
- Around 46% texted or called at least once after lights out.
Each activity was linked with less restful sleep.
The interruptions didn’t stop once kids drifted off. About one in four reported being woken up at least once in the past week by calls, texts, or emails. A similar share admitted to picking their devices back up if they woke during the night. While not the majority, these nighttime disruptions matter, especially since puberty naturally pushes teens toward later bedtimes, already making it harder to get enough rest.
Age 13 stood out as a vulnerable moment. Peer relationships become more intense, and so does the fear of missing out. Social media platforms tap into this with streaks, disappearing messages, and never-ending feeds that make it harder to put the phone down, even when sleep should be the priority.
Sleep Gaps Across Demographics
The study also revealed that bedtime screen use isn’t the same for everyone. Girls reported using screens in bed more than boys for nearly every activity, except video games. Boys, however, showed stronger links between screen use and nighttime disturbances, while girls showed stronger ties between bedtime screen use and reduced total sleep time.
Family income and education levels also played a role. Kids from lower-income households and those with parents who had less formal education were more likely to use devices in bed. Black, Latino, and Native American adolescents reported more bedtime screen use than White peers, regardless of family income or education. Asian adolescents, on the other hand, reported lower use on average.
Sexual minority adolescents (those who identified as gay, bisexual, or questioning) also reported higher bedtime screen use. But in their case, this did not come with worse sleep outcomes. Researchers suggest that online spaces may play a different role here, providing important opportunities for identity exploration and community connection.
These differences highlight how larger social factors shape bedtime screen habits. While the study didn’t measure things like neighborhood safety or targeted marketing, other research suggests that these influences matter. The takeaway is that sleep habits aren’t just about personal choice; they’re shaped by the environments teens grow up in.
Looking Forward
This study is one of the largest and most detailed looks at bedtime screen use in early adolescence. It captures the exact moment when social media eligibility kicks in and shows how quickly that change can affect nighttime routines.
Thirteen, then, is not just another candle on the birthday cake. It’s a “digital cliff” of sorts where childhood sleep routines collide with the most attention-grabbing tools of the online world. For parents, doctors, and policymakers, recognizing this shift opens a window for timely action.
The researchers suggest that pediatricians and educators give anticipatory guidance, that is, practical advice offered before problems take hold, about limiting bedtime screen use. They also recommend that family media plans, like those promoted by the American Academy of Pediatrics, include clear guidelines for keeping devices out of bed.
Importantly, solutions are unlikely to come from simple rules like “turn it off.” Community programs, culturally relevant messaging, and safe alternatives for evening activities may be more effective at helping families and teens build healthy nighttime routines.
Paper Summary
Methodology
Researchers analyzed data from 10,305 adolescents, ages 12–13, in the ABCD Study. Teens completed questionnaires about seven types of bedtime screen use (videos, games, music, texting, social media, browsing, and studying). Caregivers reported on sleep disturbances, while teens reported their own sleep duration.
Results
Older age within the 12–13 range, female sex, sexual minority identity, lower household income, lower parental education, and Black, Latino, and Native American backgrounds were linked to more bedtime screen use. More screen use in bed was associated with more sleep disturbances and shorter sleep duration. Boys showed stronger links between screen use and sleep problems, while girls showed stronger links with reduced sleep length.
Limitations
Because the study was cross-sectional, it cannot prove that screen use caused sleep problems. All data relied on self-report, which can introduce error. The study also took place during the COVID-19 pandemic, which may have influenced both sleep and screen use.
Funding and Disclosures
Dr. Jason Nagata was supported by the National Institutes of Health and the Doris Duke Charitable Foundation. The ABCD Study is funded by the NIH and other federal partners. The authors reported no conflicts of interest.
Publication Information
“Social epidemiology of bedtime screen use behaviors and sleep outcomes in early adolescence,” Jason M. Nagata et al., Sleep Health: Journal of the National Sleep Foundation, Volume 11 (2025), pp. 562–571, June 18, 2025.
1) Devices need a “bedtime” – they get put in their own spot at or before bedtime. (NOT in a bedroom for the night.)
2) Give your kids old-fashioned real alarm clocks – no phones or other connected devices as an alarm clock.
3) Check on kids and enforce the rules – take the device into a parent’s bedroom for the night if needed.
4) Make other options available for bedtime – like physical books. (But only for a reasonable amount of time – if you have an avid reader they still might need rules! Even in the days of digital everything, I have 2 avid readers – both were caught with flashlights after lights out when they were little and now teenagers both sometimes still need to be reminded to turn the lights off!)
5) MODEL these things as parents! Our kids see what we do more so than they hear what we tell them. We as parents should be able to use a real alarm clock and to put your phone/device away at night.