In Beyond the Pleasure Principle, Freud (1920) concluded that repetitive posttraumatic dreams did not serve the function of fulfilling wishes but were

helping to carry out another task, which must be accomplished before the dominance of the pleasure principle can even begin. These dreams are endea­ vouring to master the [traumatic] stimulus retrospec­ tively, by developing the anxiety whose omission was the cause of the traumatic neurosis [p. 32] .