The relationship between negative life events and non-suicidal self-injury (NSSI) among Chinese junior high school students: the mediating role of emotions

Background Adolescent non-suicidal self-injury (NSSI) is common and adolescence is the most common period of first self-injury, and the occurrence of NSSI is influenced by negative life events and emotional symptoms. The mediating role of emotional symptoms in the interaction between negative life events and NSSI has not been carefully investigated yet. Methods For middle school students in three schools in a Chinese province, the Adolescents Self-Harm Scale was used to investigate NSSI, the Adolescent Self-Rating Life Events Check List was used to investigate adolescent negative life events, and the Self-Rating Anxiety Scale and Self-Rating Depression Scale were used to assess their emotional symptoms. After the description of general data and the test for differences between groups, the relationship between negative life events, emotional symptoms and NSSI was analyzed using Pearson correlation analysis. Structural equation modeling was used to analyze the mediating role of emotions in negative life events and NSSI. Results A total of 2376 junior high school students completed this survey, which revealed an annual NSSI prevalence of 37.1% (n = 881) and a higher prevalence of NSSI among girls and rural adolescents. Among adolescents who developed NSSI, 67.4% (N = 594) used multiple means of self-injury. The most common means of self-injury was hair pulling (51.0%), and the most common NSSI purpose and external factors/events were venting bad emotions or feelings (57.5%) and poor academic performance (44.9%), respectively. Negative life events, emotional symptoms and NSSI were positively associated (P < 0.05). Structural equation modeling with negative life events, emotional symptoms and NSSI as variables showed that the model-fit index matched the data well, with RMSEA = 0.073, AGFI = 0.945, GFI = 0.980, CFI = 0.985, NFI = 0.982, TLI = 0.968, IFI = 0.985, and negative life events, emotional symptoms (anxiety, depression) and NSSI all had direct effects with standardized path coefficients of 0.16, 0.19, and 0.23, respectively, with negative life events playing an indirect role in NSSI through emotional symptoms and emotional symptoms playing an incomplete mediating role in negative life events and NSSI. Conclusion The prevalence of NSSI was higher among Chinese junior high school students. Both negative life events and emotional symptoms were direct risk factors for NSSI. In addition, negative life events were also indirect risk factors for NSSI, and emotional symptoms played an incomplete mediating role in the relationship between the effects of negative life events and NSSI. This indicates that the combination of reducing the frequency of negative life events while maintaining individual emotional stability during adolescent development can effectively reduce the prevalence of NSSI in adolescents.