Moral injury (MI) and post traumatic stress disorder (PTSD) frequently co-occur in military, emergency, and high-stakes civilian contexts, yet they represent fundamentally different forms of psychological injury. While PTSD is well established as a fear based disorder organised around threat detection and survival systems, moral injury arises from violations of deeply held moral beliefs, leading to guilt, shame, identity disruption, and existential distress.

This presentation advances an integrative neurobiological framework that distinguishes these conditions at the level of large scale brain network dynamics. Drawing on emerging neuroimaging research, PTSD is conceptualised as a salience network (SN) dominant state characterised by hyperactive threat detection and impaired top down regulation. In contrast, moral injury is associated with overactivation of the default mode network (DMN), reflecting persistent self-referential processing, moral evaluation, and disruption to identity and meaning systems.

Importantly, when MI and PTSD co-occur, a hybrid network pattern emerges involving dysregulated interaction between the DMN, salience network, and sensorimotor systems. This can result in the binding of autobiographical memory, moral appraisal, and embodied experience, contributing to persistent and treatment resistant presentations.

These distinctions have direct clinical implications. Conventional PTSD treatments targeting fear extinction may not adequately address the moral and identity based dimensions of distress. Effective intervention for moral injury requires a broader, network informed approach incorporating moral repair, meaning making, and integration of cognitive and somatic processes.

This presentation provides clinicians and researchers with a contemporary framework for understanding trauma related disorders beyond fear based models, supporting a shift toward precision, mechanism informed care in both military and civilian populations.