Prolonged exposure is rooted in the theory of emotional processing, in which new, accurate information challenges previously learned fear structures and modifies them in such a way that the new, accurate information is more readily retrieved. With PTSD, it is thought that traumatic events cause inaccurate associations to develop, between stimuli and responses from the event. These inaccurate associations lead to avoidance of trauma-related stimuli, which acts as a barrier to emotional processing.
