The cumulative effect of childhood trauma and school bullying on non-suicidal self-injury among young adults: An XGBoost model and network analysis.

BACKGROUND

Non-suicidal self-injury (NSSI) is a severe mental health concern, particularly among the youth with experiences of childhood trauma (CT) and school bullying (SB).

OBJECTIVES

This study aims to examine the cumulative and specific effects of CT and SB on NSSI, and to investigate associations between NSSI-related factors.

METHODS

A cross-sectional study involving 96,218 students from 63 colleges in Jilin Province, China, used assessments for CT, SB, and NSSI. The entropy-balancing (EB) approach was applied to achieve covariate balance between NSSI and non-NSSI groups. We quantified the cumulative effects of CT and SB on NSSI, applied the XGBoost machine learning model to explore the specific effects of CT and SB subtypes on NSSI, and utilized network analysis to investigate the interactive associations across NSSI-related factors (self-compassion, help-seeking intention, fear of happiness, virtual life orientation, social anxiety) across four subgroups: reference, SB-only, CT-only, and dual exposures.

RESULTS

The prevalence of NSSI was 8.64 % (95 % CI = 8.46-8.82 %) among young adults in Jilin province. Youths exposed to both CT and SB had a significantly greater NSSI risk than the non-exposure group (OR = 9.84, 95 % CI = 9.13-10.60, p < 0.001). The predictive model demonstrated good performance (AUC = 0.77; sensitivity = 0.68, specificity = 0.74), identifying emotional abuse, emotional neglect, and sexual abuse as key NSSI predictors. Network analysis revealed that the dual exposure subgroup exhibited stronger associations between "fear of happiness" and "virtual life orientation" and weaker associations between "self-compassion" and "help-seeking" compared to the other subgroups.

CONCLUSIONS

Individuals with experiences of CT and SB are at higher risk for NSSI. They tend to exhibit virtual life orientation and fear of happiness and are less inclined to seek help. Targeted interventions and appropriate support from authorities and educational institutions are needed to mitigate NSSI risk and improve young adults' quality of life.