After US involvement in the Vietnam War came to an end, the startling number of traumatized vets served as a stimulus for psychological research and led to the recognition of the symptoms of post-traumatic stress.
美國在越戰結束後，由於受創的軍人數目驚人，展開系統性和大規模的精神、心理研究，確定了創傷後出現壓力異常的癥狀。