Latent Classes of Addictive Features Mediate Functional Impairment and Severity in Non-Suicidal Self-Injury Among Adolescents With Mood Disorders

Background: Non-suicidal self-injury (NSSI) is prevalent among adolescents with mood disorders and often exhibits addictive features. However, the specific subgroups of addictive features and their associations with the functions and severity of NSSI remain unclear. Methods: Between September 2023 and January 2024, this study recruited 182 adolescents aged 10–24 years with mood disorders who engaged in NSSI in the past year. Participants completed assessments including: sociodemographic and clinical characteristics (general questionnaire), depressive symptoms, Hamilton Depression Rating Scale (HAMD), manic symptoms, Young Mania Rating Scale (YMRS), and NSSI addictive features, functions, and severity via the Ottawa Self-Injury Inventory-Chinese Revised Version (OSI-CRV). Latent class analysis (LCA) was employed to identify subgroups based on the 7 items of the addictive features subscale in OSI-CRV. Covariate analysis and mediation analysis were employed to distinguish the associations of latent classes of addictive features with different functions and the severity of NSSI. Results: LCA identified two distinct classes: High Addiction Class (50.0%) and Low Addiction Class (50.0%). Covariate analysis revealed that patients with younger age (odds ratio [OR] = 0.441, p = 0.017), higher educational level (OR = 0.385, p = 0.043), and greater depressive severity (moderate and severe, OR = 4.500, 4.830; p = 0.046, 0.017) were associated with High Addiction Class. Mediation analysis demonstrated that these addictive features classes indirectly mediated the association between NSSI functions and severity. Conclusions: These findings highlight the diversity of addictive features and their impact on NSSI, thereby guiding the development of tailored interventions that address the heterogeneity of addictive features.