The authors conducted an exploratory study of the nature and course of reactivation of combat-related posttraumatic stress disorder. Experienced psychiatrists, they each independently assessed 35 men with recurrent combat-related posttraumatic stress disorder. Two major types of reactivated posttraumatic stress disorder, each representing a different degree of pathology, were delineated: uncomplicated reactivation and heightened vulnerability. The second category was further subdivided into specific sensitive, moderate generalized sensitivity, and severe generalized sensitivity. The authors conclude that reactivation of war-related trauma is a complex phenomenon that may take different forms.