Dimensions of non-suicidal self-injury in suicidal adolescents: the differential role of personality pathology and suicidal ideation

Non-suicidal self-injury (NSSI) is a widespread phenomenon in adolescence. Although NSSI is conceptually distinct from suicidal behavior, the two conditions frequently co-occur and may share underlying psychopathological pathways. In particular, borderline personality disorder (BPD) has long been considered a key factor in the emergence and persistence of NSSI. However, recent evidence suggests that other dimensions of personality pathology, together with mood disorders and suicidal ideation, may significantly influence the onset, severity, and course of self-injurious behaviors in adolescence. Clarifying these relationships is crucial for clinical assessment and prevention strategies. We examined 118 adolescents admitted to a pediatric hospital for suicidal ideation or attempts. Standardized interviews (C-SSRS, K-SADS, SCID-II) were administered to assess suicidal ideation, NSSI characteristics, personality pathology, and mood disorders. NSSI was evaluated in terms of presence, duration, frequency, and severity over a 9-month observation window. Correlational, linear, and logistic regression were conducted to examine associations between NSSI outcomes and personality pathology, mood disorders, early life adversity, and suicidal ideation. Borderline personality features emerged as significant predictors of NSSI severity and duration, whereas broader non-borderline personality pathology specifically predicted repetitive high-frequency self-harm patterns. Suicidal ideation was associated with prolonged duration of NSSI but did not independently predict high-frequency self-harm. Mood disorders showed limited independent predictive value. These findings suggests differentiated pathways linking personality pathology and suicidal ideation to distinct clinical dimensions of adolescent NSSI. Integrating the assessment of personality dysfunction with evaluation of suicidal ideation may enhance clinical management and prevention strategies for adolescents at risk.