Non-Suicidal Self-Injury in Adolescents with Major Depressive Disorder: The Role of Chronotype and Anhedonia

Background: Non-suicidal self-injury (NSSI) is a common behavior among adolescents with major depressive disorder (MDD). Although depression severity is often emphasized, emerging evidence suggests that anhedonia and circadian characteristics may also contribute to NSSI. This study examined associations between NSSI, anhedonia, and chronotype in adolescents with MDD.Methods: The study included 104 adolescents (aged 12–18 years) with MDD, divided into NSSI+ (n = 52) and NSSI− (n = 52) groups. NSSI was assessed through a clinical interview based on Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR) criteria. Depression severity, anhedonia, and chronotype were assessed using the Beck Depression Inventory (BDI), Snaith–Hamilton Pleasure Scale (SHAPS), and Children’s Chronotype Questionnaire (CCTQ). Group comparisons, correlation analyses, and hierarchical logistic regression models were performed.Results: Adolescents with NSSI showed significantly higher SHAPS (p < 0.001), BDI (p = 0.007), and CCTQ scores (p < 0.001). SHAPS and CCTQ scores showed moderate positive correlations with NSSI (both p < 0.001), whereas BDI scores showed a weaker association (p = 0.007). In regression analyses, parental psychiatric history (p = 0.006), SHAPS (p = 0.027), and CCTQ scores (p = 0.018) remained significant independent predictors of NSSI, whereas BDI scores lost statistical significance (p = 0.621).Conclusion: The findings of the present study suggest that NSSI in adolescents with MDD may show stronger associations with specific dimensions such as anhedonia and circadian characteristics than with overall depression severity.