Rosh Psychiatry Board Practice Exam

A critical factor that distinguishes a diagnosis of post-traumatic stress disorder (PTSD) from acute stress disorder is the duration of symptoms experienced by the individual. According to diagnostic criteria, acute stress disorder is characterized by symptoms that occur immediately after a traumatic event but last for a minimum of three days and can persist for up to a month. If the symptoms last longer than one month, the individual may then meet the criteria for PTSD.

In the context of a patient experiencing flashbacks and nightmares following military deployment, the timing of symptom onset and their persistence play a vital role in the diagnosis. If these symptoms have been present for over a month, PTSD is diagnosed; if they are between three days and one month following the trauma, acute stress disorder would be more appropriate.

The other options, such as headaches, insomnia, and nightmares, are symptoms that can appear in both PTSD and acute stress disorder and do not serve as distinguishing factors between the two diagnoses. Thus, the critical factor that differentiates these disorders is the duration of symptomatology.