Controlled studies examining the relationship between psychiatric disorders and war and other traumatic events are reviewed. Several studies have found a correlation between the severity of posttraumatic stress disorder symptoms and the degree of trauma. Other disorders associated with trauma include depression, substance abuse disorders, adjustment disorders, psychosomatic disorders, and antisocial behavior. No relationship has been found between trauma and subsequent violent behavior. The authors identify areas for further research, including examination of why the majority of persons exposed to trauma do not develop psychiatric illness.