Predictive value of antioxidant and thyroid function indicators for non-suicidal self-injury in adolescents with...

Non-suicidal self-injury (NSSI) is highly prevalent in adolescents with major depressive disorder (MDD); however, its underlying pathophysiological mechanisms remain incompletely elucidated. Emerging evidence suggests a potential association between antioxidant markers, thyroid function parameters, and the occurrence of NSSI, although research in this domain remains limited. Accordingly, this study aimed to investigate the predictive efficacy of combining antioxidant and thyroid biomarkers with clinical symptoms for NSSI in adolescents with MDD.

This study recruited 162 adolescents with MDD between September 2022 and January 2026. Participants were stratified into groups based on the presence or absence of NSSI, in accordance with DSM-5 diagnostic criteria. Multidimensional scales were employed to assess the severity of depression, anxiety, perceived stress, and internet addiction (IA). Concurrently, blood samples were collected to measure bilirubin levels and thyroid function parameters. Stepwise logistic regression analysis was subsequently performed to identify independent risk factors associated with NSSI. Finally, receiver operating characteristic (ROC) curves were constructed to quantify the predictive performance of these identified independent factors.

The prevalence of NSSI in adolescents with MDD was 57.4%. Multivariate logistic regression analysis identified females (OR = 2.246, 95% CI = 1.032-4.888, P = 0.041), HAMD-17 score (OR = 1.183, 95% CI = 1.088-1.286, P < 0.001), indirect bilirubin (OR = 0.890, 95% CI = 0.797-0.995, P = 0.040), and TSH (OR = 2.060, 95% CI = 1.254-3.385, P = 0.004) as independent predictors of NSSI. Furthermore, ROC curve analysis further demonstrated that the four-item combination of sex, HAMD-17 score, indirect bilirubin, and TSH (AUC = 0.776, 95% CI = 0.701-0.850, P < 0.001) had a better ability to identify NSSI.

Adolescents with MDD, particularly females, represent a high-risk population for NSSI. Reduced levels of indirect bilirubin coupled with elevated TSH levels may constitute the underlying pathophysiological basis of NSSI and demonstrate significant clinical predictive value. In the future, targeted intervention strategies focusing on the antioxidant defense system and thyroid function may offer novel therapeutic avenues for the management of NSSI.