A 30-year-old male combat veteran presents to a VA clinic reporting nightmares, hypervigilance, emotional numbness, avoidance of crowded places and loud noises, and intrusive memories of a specific combat incident. The traumatic event occurred 5 weeks ago. He was diagnosed with acute stress disorder at a field hospital 2 weeks after the event. His symptoms have persisted and worsened since that initial evaluation, with new onset of irritable outbursts and concentration difficulties. Based on DSM-5-TR timing criteria, the PMHNP should now diagnose: