An online dynamic nomogram for estimating NSSI behavior among adolescents with depressive disorder

Non-suicidal self-injury (NSSI) is highly prevalent among adolescents with depressive disorder and is associated with significantly worsened clinical outcomes. Previous researches have established a link between NSSI and impairments in emotion regulation. This study aimed to quantitatively investigate the relationship between specific emotion regulation strategies and NSSI, and to develop and validate a clinically applicable nomogram for estimating the likelihood of NSSI for individual patients in this population. We recruited 1946 adolescents with depressive disorder from January 2021 to December 2021. The participants were randomly divided into a training group (70%) for model development and a validation group (30%) for testing. Using multivariate regression analysis on the training data, we identified independent correlates of NSSI and constructed a nomogram. The model subsequently underwent internal and external validation to assess its discriminative ability, calibration, and clinical utility. Multivariate analysis identified age, gender, cognitive reappraisal and PHQ-9 score as independent correlates for NSSI. These four candidates were applied to develop a nomogram. For internal validation, the p-value for the HL goodness of fit test was 0.218 (p > 0.05). The nomogram presented a C-statistic value of 73.4% (95%CI: 0.703-0.765), good calibration (Emax = 0.091, Eavg = 0.016, S:p = 0.826). Decision curve analysis suggested that the nomogram provided net benefit across a range of threshold probabilities (range: 19.9%-96.9%). For external validation using data in validation group, the p-value for the HL goodness of fit test was 0. 329 (p > 0.05). The C-statistic value was 73.4% (95%CI: 0.689-0.779), presenting good calibration (Emax = 0.052, Eavg = 0.025, S:p = 0.428) and a spectrum of estimated probabilities ranging 25.8% to 96.9%. The proposed nomogram provides a clinically applicable tool for risk stratification of NSSI among adolescents with depressive disorder. Furthermore, it identifies two modifiable correlates—cognitive reappraisal capacity and depression severity—that were significantly associated with NSSI and could be explored as potential targets for future research. Not applicable.