US Study Finds Nighttime Screen Use Harmful to Teen Sleep and Mental Health

A large clinical study in the United States observed that more than half of adolescents keep their smartphones active between 10 p.m. and 6 a.m., a habit described as "doomscrolling." The prolonged exposure to blue‑light screens and constant notifications disrupted melatonin production, leading to fragmented sleep and reduced cognitive performance, which in turn lowered school achievement.

Researchers, including Dr. Mary A. Carskadon of Brown University and Dr. Jason M. Nagata of UCLA, reported that teens who used phones during these hours showed higher irritability, anxiety, depressive symptoms and an elevated risk of self‑harm. About 20 % of participants woke up and reflexively checked their screens. Experts urged families to adopt coordinated media‑use plans to protect sleep and mental health.