Background: Previous studies have demonstrated a strong association between recent stressful life events and non-suicidal self-injury (NSSI) among adolescents. Internalizing symptoms and difficulty in emotion regulation (DER) may mediate this relationship. This study aimed to investigate the relationship between recent stressful life events and NSSI severity in adolescents and the potential moderating role of internalizing symptoms and DER.
Methods: A total of 224 adolescent inpatients (78.6% female) participated in the study, with an age range of 12– 18 years old. Data on recent stressful life events, internalizing symptoms, DER, and NSSI behaviors were collected using a clinician-rated questionnaire. A structural equation model was used to test the hypothesized model.
Results: The rate of NSSI reporting among adolescents in the past 12 months was 65.18%. Recent stressful life events were found to be directly associated with NSSI severity (β = 0.128, P = 0.023). A chain-mediating effect between recent stressful life events and NSSI was also confirmed (β = 0.034, P = 0.023), with DER and internalizing symptoms playing a chain-mediating role and DER having a significantly indirect association with NSSI through internalizing symptoms.
Conclusion: Recent stressful life events appear to play a role in the etiology of NSSI, particularly punishment and interpersonal relationship events that warrant special attention. DER and internalizing symptoms play a chain-mediating role in the relationship between life events and NSSI. Reducing recent stressful life events, screening for internalizing symptoms, and improving emotion regulation may decrease NSSI behavior among adolescents.

Keywords: non-suicidal self-injury, adolescents, recent stressful life events, internalizing symptoms, difficulty in emotion regulation, structural