title: Are Mental Health Effects of Internet Use Attributable to the Web-Based Content or Perceived Consequences of Usage? A Longitudinal Study of European Adolescents.
abstract: BACKGROUND
  Adolescents and young adults are among the most frequent Internet users, and accumulating evidence suggests that their Internet behaviors might affect their mental health. Internet use may impact mental health because certain Web-based content could be distressing. It is also possible that excessive use, regardless of content, produces negative consequences, such as neglect of protective offline activities.
  
  
  OBJECTIVE
  The objective of this study was to assess how mental health is associated with (1) the time spent on the Internet, (2) the time spent on different Web-based activities (social media use, gaming, gambling, pornography use, school work, newsreading, and targeted information searches), and (3) the perceived consequences of engaging in those activities.
  
  
  METHODS
  A random sample of 2286 adolescents was recruited from state schools in Estonia, Hungary, Italy, Lithuania, Spain, Sweden, and the United Kingdom. Questionnaire data comprising Internet behaviors and mental health variables were collected and analyzed cross-sectionally and were followed up after 4 months.
  
  
  RESULTS
  Cross-sectionally, both the time spent on the Internet and the relative time spent on various activities predicted mental health (P<.001), explaining 1.4% and 2.8% variance, respectively. However, the consequences of engaging in those activities were more important predictors, explaining 11.1% variance. Only Web-based gaming, gambling, and targeted searches had mental health effects that were not fully accounted for by perceived consequences. The longitudinal analyses showed that sleep loss due to Internet use (ß=.12, 95% CI=0.05-0.19, P=.001) and withdrawal (negative mood) when Internet could not be accessed (ß=.09, 95% CI=0.03-0.16, P<.01) were the only consequences that had a direct effect on mental health in the long term. Perceived positive consequences of Internet use did not seem to be associated with mental health at all.
  
  
  CONCLUSIONS
  The magnitude of Internet use is negatively associated with mental health in general, but specific Web-based activities differ in how consistently, how much, and in what direction they affect mental health. Consequences of Internet use (especially sleep loss and withdrawal when Internet cannot be accessed) seem to predict mental health outcomes to a greater extent than the specific activities themselves. Interventions aimed at reducing the negative mental health effects of Internet use could target its negative consequences instead of the Internet use itself.
  
  
  BACKGROUND
  International Standard Randomized Controlled Trial Number (ISRCTN): 65120704; http://www.isrctn.com/ISRCTN65120704?q=&filters=recruitmentCountry:Lithuania&sort=&offset= 5&totalResults=32&page=1&pageSize=10&searchType=basic-search (Archived by WebCite at http://www.webcitation/abcdefg).
authors.affiliation: National Centre for Suicide Research and Prevention of Mental Ill-Health, Department of Learning, Informatics, Management and Ethics, Karolinska Institutet, Stockholm, Sweden. sebastian.hokby@ki.se.
authors.forename: Sebastian
authors.identifier: http://orcid.org/0000-0002-6248-6945
authors.initials: S
authors.lastname: Hökby
authors.forename: Gergö
authors.identifier: http://orcid.org/0000-0002-0556-6244
authors.initials: G
authors.lastname: Hadlaczky
authors.forename: Joakim
authors.identifier: http://orcid.org/0000-0002-2461-351X
authors.initials: J
authors.lastname: Westerlund
authors.forename: Danuta
authors.identifier: http://orcid.org/0000-0002-8436-3989
authors.initials: D
authors.lastname: Wasserman
authors.forename: Judit
authors.identifier: http://orcid.org/0000-0002-3587-6892
authors.initials: J
authors.lastname: Balazs
authors.forename: Arunas
authors.identifier: http://orcid.org/0000-0002-1226-1449
authors.initials: A
authors.lastname: Germanavicius
authors.forename: Núria
authors.identifier: http://orcid.org/0000-0003-1454-7958
authors.initials: N
authors.lastname: Machín
authors.forename: Gergely
authors.identifier: http://orcid.org/0000-0003-3255-1029
authors.initials: G
authors.lastname: Meszaros
authors.forename: Marco
authors.identifier: http://orcid.org/0000-0001-9583-3117
authors.initials: M
authors.lastname: Sarchiapone
authors.forename: Airi
authors.identifier: http://orcid.org/0000-0003-0849-5741
authors.initials: A
authors.lastname: Värnik
authors.forename: Peeter
authors.identifier: http://orcid.org/0000-0003-3911-9140
authors.initials: P
authors.lastname: Varnik
authors.forename: Michael
authors.identifier: http://orcid.org/0000-0003-2014-2877
authors.initials: M
authors.lastname: Westerlund
authors.forename: Vladimir
authors.identifier: http://orcid.org/0000-0001-6922-0675
authors.initials: V
authors.lastname: Carli
keywords: Internet; addictive behavior; adolescent health; longitudinal study; mental health; problematic Internet use