This study investigates the neural dynamics underlying non‑suicidal self‑injury (NSSI) in depressed adolescents. We recorded EEG from 106 participants (67 with NSSI, DN+; 39 without NSSI, DN-) while they experienced social pain, physical pain, and resting‑state conditions, and performed microstate analysis.\ \ To capture higher‑order dependencies in microstate sequences, we built an interpretable deep sequence model that integrates disease‑specific, domain‑adversarial, consistency, and contrastive learning objectives. Under the social‑pain condition the model discriminated DN+ from DN‑ with 68.55% accuracy, an 8.94‑point gain over the strongest baseline.\ \ Model interpretation and conventional microstate statistics both revealed a marked weakening of bidirectional transitions between MS3 and MS5 in DN+ adolescents during social pain. Source reconstruction linked MS3 to emotional/interoceptive processing and MS5 to action preparation, suggesting disrupted emotion‑action coupling. Time‑resolved analysis showed that DN+ youths recruited action‑related states earlier (early‑to‑mid epoch) and emotional states later, whereas DN‑ youths displayed the opposite temporal order.\ \ In the DN‑ group, MS5→MS3 transitions mediated the relationship between social‑evaluation sensitivity and affective outcomes; this mediation was absent in DN+. Conversely, MS3→MS5 transitions correlated with heightened negative affect in DN+.\ \ Together, these findings identify impaired emotion‑action coupling as a key neurodynamic mechanism behind altered social‑pain processing in adolescents with NSSI, offering a mechanistically interpretable neural signature for objective NSSI identification.\ \ Review