US Study Finds Teens Lose Sleep Due to Nighttime Phone Use

A new research study led by Jason M. Nagata, associate professor of pediatrics at the University of California, San Francisco, analyzed data from the Adolescent Brain Cognitive Development Study. It found that more than half of teenagers in the United States spend an hour or longer on their phones between 10 p.m. and 6 a.m. on school nights, with many using devices between midnight and 4 a.m. This nighttime screen time shortens sleep duration, falling below the American Academy of Pediatrics' recommendation of 8‑10 hours per night.

Although the study does not directly link phone use to adverse outcomes, prior research shows that reduced sleep impairs cognitive function, emotional regulation, and increases anxiety and depressive symptoms. Mary A. Carskadon, professor of psychiatry at Brown University, noted that insufficient sleep makes adolescents more irritable and prone to mental‑health risks, including suicidal ideation. Teens reported using apps such as YouTube, Instagram and TikTok for an average of 33 minutes each night.

The findings highlight growing concerns about “doomscrolling” and its impact on adolescent health, prompting calls for parents and clinicians to monitor nighttime device use.