The aim is to examine associations between bullying involvement in adolescence and mental health problems in adulthood. 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). 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. Involvement in bullying in adolescence is associated with later mental health problems, possibly hindering development into independent adulthood.

The objective was to examine the associations of socioecological connectedness with bullying victimization and depressive symptoms in early adolescence and with non-suicidal self-injury (NSSI) in mid-adolescence, and how these might differ between genders. Diverse adolescents (N = 4115; 49.1% girls) in the 7th grade reported on connections with parents/family, peers, school, and neighborhood, as well as bullying victimization and depressive symptoms, and NSSI in 10th grade (M^e = 16.1 years). Structural equation modeling with WSLMV indicated that the lower likelihood of NSSI in 10th grade was associated with higher perceptions of connections between adolescents and their families, both directly as well as indirectly through reduced bully victimization and depressive symptoms three years earlier. Higher school connectedness was indirectly associated with the lower likelihood of NSSI through bullying victimization and depressive symptoms. Paths to NSSI varied for girls and boys. Results advance the understanding of developmental pathways leading to NSSI in adolescent girls and boys.