OBJECTIVE: Prolonged Exposure for Primary Care (PE-PC) leverages an opportunity to provide evidence-based posttraumatic stress disorder (PTSD) care in the PC setting where many veterans present for services and can greatly increase treatment access. However, such acute, short-term intervention may not be effective for all PTSD patients. METHOD: We analyzed data from a randomized clinical trial evaluating PE-PC to determine who may or may not benefit from PE-PC. We identified both PTSD symptom and general functioning trajectories for veterans with chronic PTSD in Veterans Administration primary care settings. RESULTS: For PTSD symptoms, four trajectory patterns emerged, and for functional impairment, three emerged. Demographics, treatment expectancy, and credibility did not predict PTSD symptom or functional impairment trajectories. While baseline depression severity and functioning were initially predictive, only baseline PTSD symptoms were predictive of PTSD symptom trajectories once this variable was considered. Similarly, while baseline depression and PTSD severity were initially predictive of functional trajectories, only baseline function was predictive of function trajectories once this variable was included. CONCLUSION: PE-PC may be particularly appropriate and effective for veterans presenting to primary care with moderate PTSD symptoms or functional impairment. Replication and examination of trajectories in a larger effectiveness sample is warranted. (PsycInfo Database Record (c) 2025 APA, all rights reserved).