Identifying Acute Stress Disorder

After experiencing intense psychological trauma from witnessing a violent event, an individual may develop various symptoms affecting their day-to-day functioning. The onset of these symptoms can lead to different diagnoses under Trauma and Stressor-Related Disorders.

Which of the following diagnoses is most specifically characterized by symptoms that unfold within three days to one month following the traumatic event, yet does not meet the criteria for Post-Traumatic Stress Disorder (PTSD)?