John is a 35-year-old firefighter with over ten years of ser…

John is a 35-year-old firefighter with over ten years of service. Six months ago, John was part of a team responding to a large apartment fire. During the operation, he encountered a devastating situation where he found two children who had not survived. Despite his efforts, he could not save them. This incident profoundly impacted him emotionally. He has been experiencing symptoms related to this event for four months. He experiences hypervigilance, flashbacks, nightmares, has a persistent negative emotional state, and he avoids situations and places where children will be present. He comes to your office and after a brief interview, you think he meets criteria for which diagnosis?