A soldier in combat has a greater chance of becoming a psychological casualty than being killed by the enemy. Indeed, 98% of those who endure sustained combat will develop symptoms of stress. The 2% who can withstand sustained combat have a “predisposition toward ‘aggressive psychopathic personalities’” (44). It was not until the 20th century that physical and logistic capabilities facilitated sustained combat for months at a time.

There are multiple forms of psychological casualties. Grossman cites several examples. Fatigue, an early symptom, causes the soldier to lose interest in activities and ultimately collapse. Soldiers can drift into confused states, in which there is a psychotic disassociation from reality and no awareness of identity or location, or experience “conversion hysteria” during or after combat that prevents them from functioning at all.

Additionally, soldiers can reach a level of anxiety that results in exhaustion and tenseness that cannot be cured by sleep. They can also go into an obsessional and compulsive state, resulting in tremors and hysterical reactions. Finally, soldiers can experience a character disorder in which personality changes can lead to rage, extreme religiosity, and ultimately “degeneration into a psychotic personality” (48). To treat these psychiatric problems, the soldier must be removed from combat.