Family functioning and dysfunctional attitudes mediate the link between childhood maltreatment and nonsuicidal self-injury in depressed college students: a moderated mediation model of anhedonia.

Objective: Childhood maltreatment is a well-established risk factor for nonsuicidal self-injury (NSSI), particularly in individuals with major depressive disorder (MDD). The psychological mechanisms are complex and not completely understood. Based on the Cognitive-Behavioral Vulnerability Model, this study aimed to investigate whether family functioning and dysfunctional attitudes act as parallel mediators of the relationship between childhood maltreatment and NSSI and anhedonia moderates the association between dysfunctional attitudes and NSSI in depressed college students. Methods: 525 college students diagnosed with MDD were recruited from the ESCID project. They completed Childhood Trauma Questionnaire (CTQ), Family Assessment Device (FAD), Dysfunctional Attitude Scale (DAS), Snaith-Hamilton Pleasure Scale (SHAPS), and a measure of NSSI. Data were analyzed using SPSS 26.0 for descriptive statistics and correlations, and Mplus 8.3 for mediation and moderated mediation analyses, employing maximum-likelihood estimation with Monte Carlo integration. Results: Childhood maltreatment showed a positive correlation with dysfunctional attitudes, anhedonia, and NSSI, while family functioning demonstrated no significant association. Mediation analyses revealed that childhood maltreatment had both a direct effect on NSSI (β = 0.125, p < 0.05, 95% CI [0.010, 0.240]) and an indirect effect through dysfunctional attitudes (β = 0.035, p < 0.05, 95% CI [0.008, 0.063]). In contrast, the mediating role of family functioning was not significant (β = -0.060, p > 0.05), as was the total indirect effect. Moderated mediation analyses showed that anhedonia significantly moderated the association between dysfunctional attitudes and NSSI (β = 0.190, p < 0.001, 95% CI [0.092, 0.288]). Simple slope tests indicated that dysfunctional attitudes exhibited a stronger correlation with NSSI in individuals with high levels of anhedonia, while this correlation became nonsignificant at lower levels. Conclusions: Our findings reveal that dysfunctional attitudes significantly mediate the link between childhood maltreatment and NSSI, while family functioning showed no mediating effect. Anhedonia amplified the impact of dysfunctional attitudes on NSSI, suggesting that cognitive and affective vulnerabilities enhance the risk of self-injury. Interventions that target dysfunctional attitudes and enhance hedonic capacity may improve prevention and treatment among maltreated youth with depression.