Teen sleep is quietly collapsing, and the device on the nightstand is a big reason why. Adolescents biologically need about nine hours a night, but many parents report their kids logging only six to seven hours on school nights, and researchers are increasingly pointing to late-evening phone use as a driver.
The stakes go beyond grogginess. Poor sleep in teens is tied to anxiety symptoms, depression symptoms, weaker peer support and trouble getting through the school day.
How Phones Disrupt the Teen Sleep Cycle
Sleep is guided by hormones. As evening arrives, the body releases melatonin to signal rest while cortisol, the alertness hormone, drops. Puberty already shifts this rhythm later, which is why many teenagers do not feel tired until close to midnight. Add a glowing screen and the delay compounds.
“Cell phones will further delay an adolescent’s sleeping phase,” Alice Hoagland, PhD, director of the Insomnia Clinic at the Rochester Regional Sleep Disorder Center, told Rochester Regional Health. “The moment someone gets on a cell phone, they are essentially preventing their cortisol levels from naturally declining because they are becoming stimulated by the phone itself or the content on the phone.”
Apps are engineered to hold attention, and that is where minutes turn into hours. “Even though someone only wanted to be on the phone for 15 minutes to watch one short video, all of a sudden, it’s 45-60 minutes later and they are still ‘going down the rabbit hole’ of watching videos,” Hoagland said.
What Problematic Media Use Actually Means
Not every hour on a screen is harmful. The concern is when use crosses into what researchers call problematic media use.
“Problematic media use includes excessive or dis-regulated use of screens, including social media or other forms of digital media such as gaming. Now, it becomes problematic when it’s both excessive and interferes with functioning, which could include trouble sleeping, problems going to school, relationship problems,” Sarah Domoff, assistant professor in the Department of Psychology at the University at Albany, told Campus Insights Media.
A 2021 study found that adolescents who used social media more frequently had later bedtimes one year later. Parental rules like keeping phones out of the bedroom were linked to earlier bedtimes and better sleep, especially among teens with lower levels of social media involvement.
A 2025 CDC study of nearly 2,000 U.S. teens found that those spending four or more hours a day on recreational screens were more likely to report anxiety symptoms, depression symptoms, poorer sleep, less physical activity and lower social and emotional support compared with peers who used screens less.
Why the Picture Is Not All Negative
“It’s very complicated, the relationship between social media use and mental health,” Domoff said. Some teens run into harmful social comparison or triggering content. Others build friendships, share hobbies or pick up new skills. Content and context, she said, largely drive the outcome.
How Parents Can Talk to Teens About Phone Habits
Yann Poncin, MD, a child psychiatrist, told Yale Medicine that parents can open the conversation with something like, “It seems like you’re on the phone so much that I don’t see you just doing homework like you used to do, so I’m just worried how healthy this is for you in terms of getting your stuff done. What do you think about that?”
He also warned against surveillance. “I don’t believe you should monitor the content of your teen’s phone, because a teenager should have privacy,” Poncin said. “An important part of the teenage years is figuring out who you are in the world.”
Linda Mayes, MD, chair of the Yale Child Study Center, compared social media to old fears about television. “Research showed that watching TV in and of itself wasn’t bad, but it began to have potentially negative effects on kids’ behavior when it was used as a babysitter,” Mayes said. Her suggestion is to ask teens how their online experiences feel rather than shaming the scrolling.
And a practical tip from Hoagland, move the phone. Keeping it out of arm’s reach at night makes 2 a.m. scrolling far less likely.
The video Social Media’s Impact on Children and Teens featuring Sarah Domoff, assistant professor in the Department of Psychology at the University at Albany, was first published on Campus Insights Media.
This article was created by content specialists using various tools, including AI.
