Combat Stress Reaction

Combat stress reaction (CSR), is a term used within the military to describe acute behavioural disorganisation seen by medical personnel as a direct result of the trauma of war. Also known as "combat fatigue," it has some overlap with the diagnosis of acute stress reaction used in civilian psychiatry. Historically, it has some link to shell shock, and can sometimes precursor post-traumatic stress disorder.

Combat stress reaction is an acute reaction including a range of behaviours resulting from the stress of battle which decrease the combatant's fighting efficiency. The most common symptoms are fatigue, slower reaction times, indecision, disconnection from one's surroundings, and inability to prioritize. Combat stress reaction is generally short-term and should not be confused with acute stress disorder, post-traumatic stress disorder, or other long-term disorders attributable to combat stress, although any of these may commence as a combat stress reaction.

The ratio of stress casualties to battle casualties varies with the intensity of the fighting, but with intense fighting it can be as high as 1:1. In low-level conflicts it can drop to 1:10 (or less).

In World War I, shell shock was considered a psychiatric illness resulting from injury to the nerves during combat. The horrors of trench warfare meant that about 10% of the fighting soldiers were killed (compared to 4.5% during World War II) and the total proportion of troops who became casualties (killed or wounded) was 56%. Whether a shell-shock sufferer was considered "wounded" or "sick" depended on the circumstances. The large proportion of World War I veterans in the European population meant that the symptoms were common to the culture.