Abstract: OBJECTIVE: Posttraumatic stress disorder (PTSD) presents with complex symptom patterns in high-risk occupational groups. We validated an eight-factor DSM-5 PTSD model of the PCL-5, distinguishing between internally and externally cued intrusions, and examined associations with resilience and suicidality among first responders and veterans. METHODS: Treatment-seeking first responders (n = 291) and veterans (n = 393) completed the PCL-5, RSES-22, and SBQ-R. Subgroup confirmatory factor analyses compared eight PTSD models; correlations tested convergent and criterion validity. RESULTS: The eight-factor model fit best in both groups, outperforming all alternatives, including the seven-factor hybrid. Separating internal and external intrusions clarified the symptom structure. PCL-5 severity correlated negatively with resilience and positively with suicidality. CONCLUSIONS: The eight-factor configuration better captures PTSD in high-trauma occupations, potentially enhancing clinical precision, and supports integrating resilience-building within transdiagnostic, preventive frameworks alongside evidence-based trauma treatments.