APA Dictionary of Psychology

any psychological reaction, ranging from mild to severe, to traumatic events in military operations. In World War I, such reactions were known as shell shock, whereas in World War II, the terms battle fatigue, combat fatigue, and combat neurosis were widely used. Adverse and persistent combat stress reactions are now categorized as posttraumatic stress disorders. Also called combat and operational stress reaction (COSR). See also combat and operational stress control; stress casualty.