The relationship between childhood trauma and non-suicidal self-injury in adolescents with depressive disorders: the mediating role of alexithymia and coping strategies

Background Non-suicidal self-injury (NSSI) is highly prevalent among adolescents with depressive disorders and is associated with adverse clinical outcomes. Childhood trauma is a well-established risk factor for NSSI, yet the psychological mechanisms underlying this association remain unclear. This study examined the mediating roles of alexithymia and coping strategies in the relationship between childhood trauma and NSSI among adolescents with depressive disorders. Methods A total of 129 patients (aged 12–18 years, mean age = 14.74) with depressive disorders and non-suicidal self-injury (NSSI) were recruited from the inpatient and outpatient departments of the hospital. Diagnostic interviews were conducted to diagnose depressive disorders and NSSI by professional psychiatrists. Demographic characteristics of those depressed adolescents were collected using a self- administered questionnaire. The Childhood Trauma Questionnaire Short Form (CTQ-SF), the Adolescent Non-suicidal Self‐injury Assessment Questionnaire (ANSAQ), the Chinese version of the 20-item Toronto Alexithymia Scale (TAS-20-C) and the Simplified Coping Style Questionnaire (SCSQ) were used to obtain information about childhood trauma experience, NSSI, alexithymia and coping. Results Emotional neglect and emotional abuse were the most prevalent trauma subtypes. Childhood trauma was positively correlated with NSSI (r = 0.599, p < 0.001), alexithymia (r = 0.525, p < 0.001), and negative coping (r = 0.338, p < 0.001), and negatively correlated with positive coping (r = –0.392, p < 0.001). Mediation analyses showed that alexithymia (β = 0.075, 17.08%) and negative coping (β = 0.032, 7.29%) partially mediated the relationship between childhood trauma and NSSI. Moreover, alexithymia and negative coping formed a significant chain mediation pathway (β = 0.028, 6.38%). Conclusions Childhood trauma contributes to NSSI both directly and indirectly via alexithymia and maladaptive coping. Targeted interventions addressing emotional awareness and coping flexibility may help reduce the risk of self-injury among adolescents with depressive disorders and trauma histories.