The first study of a mentalizing mediator model in a community sample of nonsuicidal self-injured adolescents and its association with salivary oxytocin.

BACKGROUND

Nonsuicidal self-injurious behavior (NSSI) is highly prevalent in adolescents and strongly associated with early trauma. Emerging theories have indicated that the occurrence of NSSI results from the interaction of individual biological vulnerability and environmental risk; however, the underlying mechanisms are not yet clear. This study sought to investigate the psychological and pathophysiological mechanisms underlying the development of self-injury behavior through environmental, psychological, and physiological factors. We hypothesized that mentalization mediates the relationship between childhood trauma and NSSI, and further explored whether oxytocin (OT) has the potential to serve as an informative biomarker of social functioning for people with NSSI.

METHODS

This study investigated NSSI, childhood trauma, and mentalizing in 1313 junior high school students to develop and test a mediated model of mentalizing in which childhood trauma affects NSSI. Subsequently, the relationship between peripheral salivary OT levels and NSSI in a cohort of 109 individuals with suicidal self-injurious behavior and 113 healthy controls.

RESULTS

The NSSI detection rate was 28.2% in this study. Females had a greater frequency of NSSI, hypomentalization and lower hypermentalization.The structural equation modeling (SEM) results revealed that the indirect effect of childhood trauma on NSSI through hypomentalization was 0.091 (95% CI [0.066, 0.120], P< 0.001). The indirect effect of childhood trauma on NSSI through hypermentalization was 0.037 (95% CI [0.025, 0.049], P < 0.001). OT levels were not significantly correlated with hypermentalization, hypomentalization, or childhood trauma ( > 0.05).

CONCLUSIONS

The present study revealed that mentalizing partially mediated the associations between childhood trauma and NSSI, suggesting that the mentalizing trauma model is equally applicable to the community NSSI population. This is the first study to explore the relationship between peripheral OT levels and NSSI behavior, with results suggesting that baseline salivary OT concentrations are not reliable biomarkers for NSSI in community samples.