title: Internet addiction: Prevalence and relation with mental states in adolescents.
abstract: OBJECTIVE
  Internet addiction disrupts the daily lives of adolescents. We investigated the prevalence of Internet addiction in junior high school students, elucidated the relation between Internet addiction and mental states, and determined the factors associated with Internet addiction in adolescents.
  
  
  METHODS
  Junior high school students (aged 12-15 years) were assessed using Young's Internet Addiction Test (IAT), the Japanese version of the General Health Questionnaire (GHQ), and a questionnaire on access to electronic devices.
  
  
  RESULTS
  Based on total IAT scores, 2.0% (male, 2.1%; female, 1.9%) and 21.7% (male, 19.8%; female, 23.6%) of the total 853 participants (response rate, 97.6%) were classified as addicted and possibly addicted, respectively. Total GHQ scores were significantly higher in the addicted (12.9 ± 7.4) and possibly addicted groups (8.8 ± 6.0) than in the non-addicted group (4.3 ± 4.6; P < 0.001, both groups). A comparison of the percentage of students in the pathological range of GHQ scores revealed significantly higher scores in the possibly addicted group than in the non-addicted group. Further, accessibility to smartphones was significantly associated with Internet addiction.
  
  
  CONCLUSIONS
  Students in the addicted and possibly addicted groups were considered 'problematic' Internet users. Use of smartphones warrants special attention, being among the top factors contributing to Internet addiction.
authors.affiliation: Department of Neuropsychiatry, Ehime University Graduate School of Medicine, and Center for Child Health, Behavior and Development, Ehime University Hospital, Toon, Japan. k_kentaro_k@yahoo.co.jp.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kawabe
authors.affiliation: Department of Neuropsychiatry, Ehime University Graduate School of Medicine, and Center for Child Health, Behavior and Development, Ehime University Hospital, Toon, Japan.
authors.forename: Fumie
authors.initials: F
authors.lastname: Horiuchi
authors.affiliation: Department of Neuropsychiatry, Ehime University Graduate School of Medicine, and Center for Child Health, Behavior and Development, Ehime University Hospital, Toon, Japan.
authors.forename: Marina
authors.initials: M
authors.lastname: Ochi
authors.affiliation: Center for Sleep Medicine and Center for Child Health, Behavior and Development, Ehime University Hospital, Toon, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Oka
authors.affiliation: Department of Neuropsychiatry, Ehime University Graduate School of Medicine, and Center for Child Health, Behavior and Development, Ehime University Hospital, Toon, Japan.
authors.forename: Shu-Ichi
authors.initials: S
authors.lastname: Ueno
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000502:physiology*; D016739:Behavior, Addictive / Q000453:epidemiology / Q000503:physiopathology*; D002648:Child; D005260:Female; D006801:Humans; D020407:Internet / Q000706:statistics & numerical data*; D007564:Japan / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D000068997:Smartphone / Q000706:statistics & numerical data*
keywords: General Health Questionnaire; Internet addiction; Young's Internet Addiction Test; adolescents; suicidal ideation