Bessel van der Kolk, MD

Trauma, by definition, is the result of exposure to an inescapably stressful event that overwhelms a person's coping mechanisms. Since it would be immoral to expose laboratory subjects to the sort of overwhelming stimuli that give rise to the dissociated sensory reexperiences characteristic of posttraumatic stress disorder (PTSD), we are uncertain to what degree the vast literature involving laboratory studies of less stressful events is relevant to understanding how people process traumatic memories.