A person must meet criteria in the American Psychiatric Association's DSM-5 in order to receive a PTSD diagnosis, explains Mayo Clinic. PTSD, or post-traumatic stress disorder, is only diagnosed after a thorough psychological evaluation.
To receive a diagnosis of PTSD, a violent event or an event that threatened death or serious injury must have occurred in the person's past, explains Mayo Clinic. If the person learned someone close to him went through such an event, that might also lead to PTSD. The DSM-5 diagnostic criteria states that PTSD symptoms include flashbacks, reliving distressing memories and images, experiencing disturbing dreams about the event, and experiencing physical symptoms or ongoing emotional distress when reminded of the event.