Abstract
INTRODUCTION: This study examined the role of loneliness (social and emotional) and ostracism in adolescents' psychological well-being (positive mental health and psychological symptoms) and substance use. Perceived teacher and family support and grade level were examined as moderators in these associations. METHODS: A total of 2241 Finnish adolescents (Grade 7: 1218, M(age) 13.90 years, 50% girls; Grade 9: 1023, M(age) 15.91 years, 52.5% girls) completed a cross-sectional self-report survey in 2022. The data were analyzed using structural equation modeling (SEM). RESULTS: Higher levels of social loneliness and perceived ostracism were associated with poorer psychological well-being, whereas higher levels of emotional loneliness were associated with frequent substance use. While high teacher support buffered against lower mental health in adolescents with high perceived ostracism, high family support buffered against lower mental health in those with high social loneliness. Higher levels of emotional loneliness were more strongly linked to frequent substance use and lower mental health in older students, whereas the negative association between social loneliness and mental health was stronger in younger students. CONCLUSION: These results suggest that it is important to identify the form of social outsiderhood adolescents experience when promoting their well-being.