Depressive symptoms and subjective cognitive dysfunction associated with non-suicidal self-injury among Chinese adolescents: the mediating role of impulsivity and the moderating role of addictive features

Background Major depressive disorder (MDD) and non-suicidal self-injury (NSSI) have a strong connection, and adolescents with MDD who engage in NSSI typically exhibit more severe subjective cognitive dysfunction. This study aimed to clarify how depressive symptoms are associated with subjective cognitive dysfunction in adolescents with NSSI, with a focus on the moderating role of addictive traits and impulsivity levels. Methods 260 adolescents aged 12–18 years with MDD were recruited and divided into the NSSI group (150 cases) and without NSSI group (110 cases). The subjects were evaluated using the Ottawa Self-Injury Inventory (OSI), Patient Health Questionnaire (PHQ-9), Barratt Impulsivity Scale (BIS-11), and Self-Cognitive Functional Deficits Scale (PDQ-D). The scores of the two groups were compared, and the roles of the impulsivity level and characteristics of self-injurious addictions in the relationships between subjective cognitive dysfunction and depressive symptoms were examined. Results In comparison to the group without NSSI, the NSSI group scored significantly higher on depressive symptoms, impulsivity level, and subjective cognitive dysfunction ( p < 0.001). Additionally, the depression scores in the group with NSSI were significantly positively correlated with the scores in addictive features, impulsivity level, and subjective cognitive dysfunction. Furthermore, impulsivity level partially mediated the increase of subjective cognitive dysfunction by depressive symptoms, with a mediation effect value of 0.118 and 95%CI=[0.004,0.249]. Conversely, there was a significant interaction term for subjective cognitive dysfunction between depressive symptoms and self-injurious addiction feature ( β = 0.063,95%CI=[0.008,0.117]). Conclusion Adolescents with MDD who have NSSI have more severe subjective cognitive dysfunction in the context of high impulsivity levels and the interaction between depressive symptoms and self-injurious addictive Features.