Teenagers who use smartphones excessively are placing their health in serious danger.
Research shows that teens who are glued to their phones for over four hours per day face a range of health risks - including psychiatric issues, sleep problems and musculoskeletal disorders.
Frequent phone users were also a lot more likely to be obese than teenagers who spent less time on their devices.
Professor Jong Ho Cha, from Hanyang University Medical Centre in South Korea, said: "Smartphones have become essential platforms in the lives of young people.
"Adolescents' daily lives are connected to smartphones for various purposes, and this trend has been accelerated by school closures and social distancing.
"As smartphone usage time increases, growing evidence suggests that the smartphone is related to many adverse health effects among adolescents."