Changes in Smartphone Usage among Adolescents and Associated Subjective Health Concerns: A Secondary Analysis of the Korea Youth Risk Behavior Survey

Background: We evaluated changes in the smartphone use rate and time among Korean adolescents and their awareness of associated health problems. Methods: This study was a secondary analysis of the Korea Youth Risk Behavior Survey (2020–2023) conducted by the Korean Disease Control and Prevention Agency. The total number of enrolled adolescents aged 12–18 years was 214,526. Results: The weekly smartphone usage rate increased from 96.4% to 97.1% (p = 0.03), with no significant changes observed in weekend usage. The average smartphone use time was 4.7 h on weekdays (p = 0.17) and 6.6 h on weekends (p = 0.37). Middle school adolescents had a higher weekday use rate than high school adolescents, but the average smartphone use time was significantly less. By 2023, the proportion of adolescents with overdependence was 28% (n = 14,672). Additionally, 11.8% (n = 6255) responded that they had experienced health problems due to smartphone use. Conclusions: The longer they used their smartphones for on the weekends, the more likely they considered their health to be worse. In conclusion, our youth population needs to be educated on the proper use of smartphones.