Cell phone use at night harms adolescents' sleep and studies, says study

Teenagers' habit of being glued to their cell phones is turning many of them into night owls on the nights before school - precisely when they need to get as much sleep as possible.

The American Academy of Pediatrics and the American Academy of Sleep Medicine recommend that teenagers sleep eight to ten hours a night. But more than half of teenagers in the United States spend up to an hour or more on their cell phones between 10pm and 6am on school nights, according to new research.

In addition, more than half of teens used their cell phones in the middle of the night, between 12 a.m. and 4 a.m., according to the study's lead author, Jason M. Nagata, associate professor of pediatrics at the University of California, San Francisco. Nagata and his colleagues analyzed data collected from the Adolescent Brain Cognitive Development Study, which shows how teens' cell phone use patterns and specific types of use disrupt sleep during nighttime hours.

Although research does not directly link late-night cell phone use to harmful consequences for teens, previous studies have shown that sleep disruption has negative impacts.

"By replacing the opportunity to sleep, it can be difficult for adolescents to get adequate sleep, and this has a downstream impact on their daytime behavior, as we have known for many, many years," said Dr. Mary A. Carskadon, professor of psychiatry and human behavior at Brown University. She did not participate in the study.

Lack of sleep has many impacts
Inadequate sleep can affect people in countless ways. For teenagers, who are at a stage where their brain and body are developing, sleep deprivation has even greater consequences.

Cognitive function is impaired when the body is not well rested. It becomes more difficult to consolidate and retain the information acquired throughout the day. "One of the tasks of life for teenagers is to learn," Carskadon said. "Whether it's learning at school, in sports, in behavior with other people, in social interactions, there is a lot of learning that accumulates throughout adolescence."

Emotional regulation worsens with inadequate sleep. In a 2013 study, a group of healthy teenagers between the ages of 14 and 17 participated in a three-week experiment that began with a typical week of sleep. Next came a week of sleep restriction with 6 and a half hours of rest per night, followed by a final week of healthy sleep with 10 hours per night.

Participants rated themselves as slightly more anxious, irritable, confused and fatigued during the sleep restriction period compared to the healthy sleep period. Teens and their parents also reported more irritability and poorer emotional regulation. "The less sleep a teenager gets, the more irritable they become," Carskadon said. "Parents will tell you it's one of those obvious conclusion types."

For certain vulnerable young people, lack of sleep can pose mental health risks. Nagata noted that previous research suggests that sleep-deprived children are at greater risk for symptoms of depression and anxiety.

Lack of sleep can also make 'teens vulnerable to suicidal ideation, self-harm and risky behaviors,' Carskadon said.

Teens focused their screen time on social networking, entertainment, gaming, communication and music apps, according to Nagata. Teens spent more time - an average of 33 minutes per night - on apps like YouTube, Instagram and TikTok.

When asked for comment, YouTube provided links to its website with information about parental controls. TikTok and Instagram did not respond to a request for comment by deadline.

Carskadon pointed to the active engagement required by most of these apps as an additional disruption to overall sleep. "When you're supposed to be sleeping, your arousal levels need to decrease, but this is the type of interaction that increases your arousal and makes it harder to sleep," Carskadon said.

Scrolling your cell phone in the early hours of the morning can delay bedtime, but vibrations, ringing and notification lights can also fragment sleep throughout the night, experts say.

There is also a behavioral cycle, or habit, associated with picking up or checking your cell phone immediately after waking up. When a notification sounds in the middle of the night, your immediate reflex is to check your device.

Nagata led a separate analysis in 2023 using data from the Adolescent Brain Cognitive Development Study. In that report, he and another team of researchers found that 17% of teens reported being woken up by calls, texts or emails at least once a night while they slept. Furthermore, 20% reported using their cell phone if they woke up during the night. "All of a sudden you see these messages and it can reactivate them and make it difficult to go back to sleep," Nagata said.

Developing a family plan
Dealing with the problem of cell phone use at night is not a task that teenagers should face alone. Building healthier habits starts with parents, Nagata and Carskadon said. Parents need to model the behavior they want to see in their teens.

Because it is a family issue, it can be more difficult to minimize or control behavior if it is not applied and expected consistently by everyone. "I think it's important for parents to model healthy screen behaviors," Nagata said. "We also found that one of the biggest predictors of teen screen use is actually parents' own screen use."

One of the recommendations of the American Academy of Pediatrics is to create a family media plan that guides the entire family to have healthy screen habits. Some suggestions include creating screen-free zones in the home and times when devices are not allowed. Establish guidelines for how long devices can be used and impose limits.

Planning activities that don't involve screens is a good way to fill time that would otherwise include a device. Keeping cellphones and other devices out of bedrooms is also recommended, and Carskadon suggests creating a "family media safe" that forces family members to physically separate themselves from their devices. "It's not just a teenage problem; it's a family problem", concludes Carskadon.

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Source: CNN