Flashbacks and reliving are in some ways worse than the trauma itself. A traumatic event has a beginning and an end — at some point it is over. But for people with PTSD a flashback can occur at any time, whether they are awake or asleep.
Van der Kolk argues that flashbacks are phenomenologically more destructive than the original trauma precisely because they lack temporal boundedness, trapping the sufferer in an open-ended loop of re-experiencing.
, The Body Keeps the Score: Brain, Mind, and Body in the Healing of Trauma, 2014thesis