Long-term effects of bullying in adolescence: Mental health and social adaptation in adulthood

The main purpose of this thesis was to investigate the long-term effects of bullying. Previous studies have shown that the effects of being bullied or bullying others during childhood and youth affect mental health and psychosocial functioning later in youth life. This applies to those who were being bullied, bully-victims, or who are aggressive toward others. However, most longitudinal studies to date have been performed within the education system. Little is known about the long-term effects of bullying among youth and how this affects mental health in (young) adulthood. In particular, we know little about how bullying may have affected social functioning in young adults. Many studies are often retrospective and examine the effects of public records (e.g., psychiatric diagnoses or criminal records). One can more strongly decide whether there are any long-term effects of bullying reported in young adulthood using a prospective study of a representative youth population. This thesis is based on the survey data from the Youth and Mental Health Study conducted by the Regional Centre for Child and Youth Mental Health and Child Welfare (RKBU Midt-Norge) formerly known as the Centre for Child and Adolescent Mental Health Central Norway (RBUP Midt-Norge). The representative sample of youth in central Norway was previously assessed in 1998 (T1, n = 2464, Mean Age (MA) 13.7 years, SD = 0.58) and 1999–2000 (T2, n = 2432, MA 14.9 years, SD = 0.60). In 2012, a 12-year follow-up study was performed (T4, n = 1266, MA = 27.2, SD = 0.59). The data consist of self-reports at all three time points. The adolescents at T1 and T2 were broadly assessed with respect to their psychological distress and psychosocial functioning, family functioning, and physical health. The same instruments were used for the follow-up survey at T4 with a few age-related adjustments. The analyses of Papers I and II were based on four groups assessed at T1 and T2, who were categorized as being bullied, bully-victims, aggressive toward others, or not involved. Paper III examines the being-bullied group with the not-involved group by gender in relation to suicidal ideation, self-harm, and attempted suicide. Adjusted for gender and parental socioeconomic status, the findings in Paper I showed that those who were being bullied, bully-victims, or who are aggressive towards others are more likely to have lower educational attainment as young adults compared with those not involved in bullying in youth. Those who were aggressive towards others in youth have an almost 3 times higher risk of being unemployed and/or receiving some form of social assistance. Those who were bully-victims in youth reported an almost 3 times higher odds ratio (OR) in having poor general health. As young adults, they reported a 2.5 times increased risk of pain than those who were not involved in bullying. Bully-victims had almost 3 times increased risk for tobacco use and reported lower job functioning than those who were not involved in bullying. Those who were bullied and those who were aggressive towards others had more than a doubled higher risk for illegal drug use than those who were not involved in bullying. The results from Paper II showed that those involved in bullying (those who were bullied, bully-victims, or aggressive towards others) had higher mean scores than the not-involved group on the total adult self-report (ASR), i.e., in total, externalizing, and internalizing problems and the critical problem scales. When comparing low-to-moderate-scorers versus high scorers (90th percentile), we found that all groups involved in bullying had higher OR of both ASR externalizing and internalizing mental health problems compared with the not-involved group. When we adjusted for the impact of mental health in youth, we found that those who were bullied still had an increased risk of depressive problems in young adulthood compared with the not-involved group. Youth who were bullied also reported reduced psychosocial functioning and increased risk to seek help for mental health problems last year and earlier in life compared with the notinvolved group. All groups involved in bullying reported between 4–8 times higher risk of hospitalization since young adolescence because of a mental health problem compared with the noninvolved group. Our main finding from Paper III is that regardless of gender, being bullied in adolescence strongly predicts suicidal attepts and self –harm. Moreover, as young adults, bullied male adolescents had the highest risk of suicide attempts and self-harm, while formerly bullied adult women had the highest risk of suicidal ideation. In conclusion, detecting and preventing bullying in early adolescence has potential to improve both psychosocial functions and mental health in young adults. More specifically, this might reduce suicidal ideation, self-harm, and suicide attempts in young adulthood. Clinical practitioners and other health-care personnel should address past bullying experiences to prevent suicidal behavior in both adolescence and young adulthood