• adolescents;
  • excessive daytime sleepiness;
  • Internet overuse;
  • Korea;
  • prevalence

Aim:  The purpose of this study was to examine the association of Internet overuse with excessive daytime sleepiness (EDS).

Methods:  A total of 2336 high school students in South Korea (boys, 57.5%; girls, 42.5%) completed the structured questionnaire. The severity of Internet addiction was evaluated using Young's Internet addiction test.

Results:  The proportions of boys who were classified as Internet addicts and possible Internet addicts were 2.5% and 53.7%, respectively. For girls, the corresponding proportions were 1.9% and 38.9%, respectively. The prevalence of EDS was 11.2% (boys, 11.2%; girls, 11.1%). When Internet addicts were compared with non-addicts, they consisted of more boys, drank alcohol more, and considered their own health condition as poor. But smoking was not related with Internet addiction. The prevalence rate of EDS for Internet addicts was 37.7%, whereas that for possible Internet addicts and non-addicts was 13.9% and 7.4%, respectively. The prevalence of insomnia, witnessed snoring, apnea, teeth grinding, and nightmares was highest in Internet addicts, middle in possible addicts, and lowest in non-addicts. With adjustment for duration of Internet use, duration of sleep time, age, gender, smoking, taking painkillers due to headache, insomnia symptoms, witnessed apnea, and nightmares, the odds of EDS were 5.2-fold greater (95% confidence interval [CI]: 2.7–10.2) in Internet addicts and 1.9-fold greater (95%CI: 1.4–2.6) in possible Internet addicts compared to non-addicts.

Conclusion:  Internet addiction is strongly associated with EDS in adolescents. Clinicians should consider examining Internet addiction in adolescent cases of EDS.