<prompt> Post traumatic stress disorder PTSD is differentiated from all other disorders by:Nightmares about eventsAutonomic arrousal and anxietyRecall of events and avoidance of similar experiences in PTSDDepression  <response>: C i.e. Recall of events and avoidance of similar experiences in PTSD- PTSD arises as response to traumatic event criteria A that is characterized by persistent re-experience criteria B, persistent avoidance and numbness C, hyperarousal D, of 1 month duration criteria E causing significant distress impaired functioning criteria FQ. The onset may be delayed 6 months to years after event.- PTSD arises as a delayedprotracted response to an exceptionally stressful or catastrophic life event or situation which is likely to cause pervasive distress in almost any person eg. disaster, war, rape, toure, serious accident. It may develop even after 6 months to years after stressorQ.- PTSD is characterized by peristentrecurrent intrusive distressing recollections of stressful event either in flashbacks images, thoughts or perceptions, dreams, reliving experiences, illusions, hallucinations or distress physiological reactivity on exposure to reminders of traumatic events. There is marked persistent avoidance of stimulievents or situations that arouse recollection of stressful events and increased arousal hyperarousal and numbing of general responsivenessQ.Paial amnesia for some aspects of stressful events, anhedonia inability to experience pleasure and alexithymia characterized by inability to identify aiculate feelings may be present. 