Clinical Boundaries of Trauma: A Conceptual Framework for Navigating Comorbidity and Diagnostic Overlap in PTSD

Post-traumatic stress disorder (PTSD) rarely occurs in isolation; over 80% of individuals present with comorbid conditions such as depression, anxiety, or substance use disorders. The polythetic DSM-5 structure creates substantial diagnostic heterogeneity, producing thousands of possible symptom combinations. This theoretical paper seeks to demonstrate how trauma-related symptoms transcend diagnostic categories and proposes a mechanism-based framework for improving differential diagnosis and treatment planning.

We review symptom overlap between PTSD and major depressive disorder, borderline personality disorder, prolonged grief disorder, and moral injury, highlighting discrepancies between DSM-5 and ICD-11 conceptualizations.

We demonstrate that trauma-related presentations reflect multidimensional suffering involving depression, dissociation, affective dysregulation, identity disturbance, grief, and moral distress. We propose a conceptual, mechanism-based framework organized around four response profiles, fear-based, grief-dominant, dissociative, and moral-injury patterns, that may capture underlying mechanisms more effectively than categorical diagnoses.

A mechanism-based approach may refine diagnostic clarity, enhance treatment precision, and better integrate the psychological and somatic dimensions of trauma.