PTSD, or post traumatic stress disorder, is different from other anxiety disorders in that PTSD is triggered by a life-threatening event. In addition, what differentiates PTSD from other anxiety disorders is that PTSD is associated with flashbacks and nightmares about that traumatic event. So PTSD is associated with a triad of symptoms, which include re-experiencing the trauma (night and flashbacks), avoidance of any reminders of the trauma, and a state of hypervigilance, where you are easily startled and constantly on-guard for any possible recurrence of the trauma.
