Neuroimaging studies of non-suicidal self-injury in young adults with major depressive disorder.

Non-suicidal self-injury (NSSI) is highly prevalent in adolescents with major depressive disorder (MDD), elevating suicide risk and indicating poor prognosis. While neuroimaging studies have examined NSSI and MDD separately, systematic reviews focusing on major depressive disorder with non-suicidal self-injury (nsMDD) remain scarce. In accordance with PRISMA guidelines, this study systematically reviewed 24 neuroimaging studies (2013 - 2025) involving 2,379 participants (mean age ≤23 years) from PubMed, PsycInfo, and Embase. Using the Newcastle-Ottawa scale for quality assessment, we found 20 functional magnetic resonance imaging (resting-state fMRI and task fMRI) and 4 structural magnetic resonance imaging (MRI) studies. Key findings identified distinct neural signatures specific to nsMDD that differentiate it from depression without NSSI, including: suppression of the frontal gyrus, reduced volume of the putamen, abnormal activation of the lingual gyrus, midline cortical structures, and the prefrontal-limbic-mesencephalic circuit. In terms of neural networks, the default mode network exhibits enhanced connectivity with other neural networks, while the frontoparietal network shows abnormal suppression. Despite limitations including cross-sectional designs, gender imbalance, and scarce multimodal data, these findings provide a basis for targeted intervention that require longitudinal validation of their clinical utility.