Adverse Childhood Experiences and Nonsuicidal Self-Injury and Suicidality in Chinese Adolescents

Importance Studies investigating the role of supportive school environments in associations between adverse childhood experiences (ACEs) and nonsuicidal self-injury (NSSI) and suicidality among adolescents are lacking. Objective To assess associations of ACEs with NSSI and suicidality among adolescents and examine the modifying role of supportive school environments in such associations. Design, Setting, and Participants Using data from the 2021 School-Based Chinese Adolescents Health Survey, this cross-sectional study includes Chinese adolescents in grades 7 through 12 from 326 schools across 8 provinces in China. Statistical analysis was performed from March to October 2024. Exposure ACEs, including individual indicators and cumulative numbers by total and categorized as threat-related and deprivation-related ACEs, were assessed. Main Outcome and Measures NSSI, suicidal ideation, and suicide attempts were measured using validated questionnaires. Weighted Poisson regression models were used. The modifying interaction of supportive school environments was assessed using multiplicative interactions. Results Among 95 549 adolescents included in this study (mean [SD] age, 14.9 [1.8] years; 47 617 males [49.8%]), 45 236 individuals (47.3%) had experienced at least 1 ACE. Compared with adolescents with no ACEs, those who experienced 4 or more ACEs had an increased risk of NSSI (prevalence ratio [PR], 1.31; 95% CI, 1.30-1.33) and suicidality (ideation: PR, 1.41; 95% CI, 1.39-1.42; attempts: PR, 1.25; 95% CI, 1.24-1.27) after adjusting for covariates, including supportive school environments. A dose-response association was observed between the number of ACEs and the risk of NSSI and suicidality (eg, NSSI: PR, 1.06; 95% CI, 1.05-1.06 for exposure to 1 vs 0 ACEs; PR, 1.10; 95% CI, 1.10-1.11 for exposure to 2 vs 0 ACEs). The highest PRs were found for associations of threat-related ACEs (eg, physical abuse, emotional abuse, and bullying) with NSSI and suicidality (eg, exposure to ≥2 vs 0 threat-related ACEs: PR, 1.28; 95% CI, 1.27-1.29 for NSSI; PR, 1.33; 95% CI 1.32-1.34 for ideation; PR, 1.18; 95% CI, 1.17-1.19 for attempts). All individual ACE indicators were positively associated with NSSI and suicidality, with particularly high PRs for emotional abuse (eg, PR, 1.26; 95% CI, 1.24-1.27 for NSSI). Additionally, supportive school environments significantly modified associations of ACEs with NSSI and suicidality (eg, interaction ratio for NSSI, 0.81; 95% CI, 0.76-0.88). Conclusion and relevance In this study, exposure to ACEs was associated with an increased risk of NSSI and suicidality, with particularly high increases for threat-related ACEs, independent of the interaction of supportive school environments, but supportive school environments could modify such detrimental outcomes. These findings underscore the importance of enhancing school environments to prevent NSSI and suicidality among adolescents who have experienced ACEs.