A psychiatric casualty is a military combatant who is unable to continue fighting due to some sort of mental debilitation. The debilitations a casualty can experience are extensive, with many psychiatric casualties developing long-term or permanent post-traumatic stress disorder. Treatment generally consists of simply removing a soldier from combat; however, psychotherapy is sometimes used. This Korean war period handbook covers syndromes, prevention and treatment, and methods used at the time. Psychiatric casualties are recognised as an important and inevitable feature of modern warfare. At the beginning of the 20th century they were scarcely acknowledged (shell shock), and still less treated. Today, as a result of lessons learned in the First and Second World Wars, numbers can be predicted on the basis of battle intensity and effective clinical interventions applied.