title: The long-term effects of being bullied or a bully in adolescence on externalizing and internalizing mental health problems in adulthood.
abstract: BACKGROUND
  The aim is to examine associations between bullying involvement in adolescence and mental health problems in adulthood.
  
  
  METHODS
  Information on bullying-involvement (being bullied, bully-victim, aggressive toward others) and non-involved was collected from 2464 adolescents in Mid-Norway at mean age 13.7 and again at mean age 14.9. Information about mental health problems and psychosocial functioning was collected about 12 years later at mean age 27.2 (n = 1266).
  
  
  RESULTS
  All groups involved in bullying in young adolescence had adverse mental health outcomes in adulthood compared to non-involved. Those being bullied were affected especially regarding increased total sum of depressive symptoms and high levels of total, internalizing and critical symptoms, increased risk of having received help for mental health problems, and reduced functioning because of a psychiatric problem in adulthood. While those being aggressive toward others showed high levels of total and internalizing symptoms. Both those being bullied and bully-victims showed an increased risk of high levels of critical symptoms. Lastly, all groups involved in bullying on adolescence had increased risk of psychiatric hospitalization because of mental health problems.
  
  
  CONCLUSIONS
  Involvement in bullying in adolescence is associated with later mental health problems, possibly hindering development into independent adulthood.
authors: Faculty of Medicine, Norwegian University of Science and Technology, The Regional Centre for Child and Youth Mental Health and Child Welfare (RKBU), P.O. Box 8905, MTFS, 7491 Trondheim, Norway.
authors: Johannes Foss
authors: JF
authors: Sigurdson
authors: Faculty of Medicine, Norwegian University of Science and Technology, The Regional Centre for Child and Youth Mental Health and Child Welfare (RKBU), P.O. Box 8905, MTFS, 7491 Trondheim, Norway.
authors: A M
authors: AM
authors: Undheim
authors: Faculty of Medicine, Norwegian University of Science and Technology, The Regional Centre for Child and Youth Mental Health and Child Welfare (RKBU), P.O. Box 8905, MTFS, 7491 Trondheim, Norway ; University of California, Merced, CA USA.
authors: J L
authors: JL
authors: Wallander
authors: Faculty of Medicine, Norwegian University of Science and Technology, The Regional Centre for Child and Youth Mental Health and Child Welfare (RKBU), P.O. Box 8905, MTFS, 7491 Trondheim, Norway.
authors: S
authors: S
authors: Lydersen
authors: Faculty of Medicine, Norwegian University of Science and Technology, The Regional Centre for Child and Youth Mental Health and Child Welfare (RKBU), P.O. Box 8905, MTFS, 7491 Trondheim, Norway ; St. Olav Hospital, Trondheim, Norway.
authors: A M
authors: AM
authors: Sund
keywords: Aggressive toward others; Being bullied; Bully–victim; Epidemiology; Longitudinal; Mental health problems