State-Level Brain Dynamics Reveal Neural Correlates of Negative-Mode Rigidity in NSSI

Non-suicidal self-injury (NSSI) is marked by persistent difficulty disengaging from aversive internal states, yet the neural dynamics that may support this clinical rigidity remain poorly understood. Intrinsic brain activity normally cycles among recurrent large-scale states, and alterations in how these states are occupied or transitioned may provide a neural analogue of negatively biased internal modes. Using resting-state fMRI from 160 patients with NSSI and 50 disease controls, we applied Hidden Markov Modeling to characterize latent brain states and their temporal properties. NSSI was associated with disproportionate engagement of a recurrent limbic-related state, reduced differentiation between states, and greater variability within states. Dominance of the limbic-related state was linked to more severe emotion-regulation difficulties at baseline and predicted less improvement in NSSI behaviors over three months. These findings indicate that NSSI involves a biased settling into affectively weighted brain states within a less distinct and less stable state landscape, suggesting that impaired brain-state flexibility constitutes a neural mechanism underlying this condition and a potential target for intervention. When considered alongside prior evidence showing heightened variability in connectivity strength and network topology, the results point to convergent disruptions in neural flexibility across multiple organizational levels in NSSI, further underscoring their mechanistic and translational relevance.