Soldiers from countries such as Great Britain and France were executed for what was then referred to as cowardice both as punishment for supposedly deserting or abandoning their military duties and as a deterrent to others who may do the same. Scholars have since determined that many of the men who were killed for cowardice were actually suffering from post-traumatic stress disorder (PTSD) or similar war-related ailments.
Thanks to the inclusion of new technologies and the sheer scope of the conflict, World War I brought about warfare on a scale the world had never seen before. Many of the men who fought in the war came home with an ailment that was then described as shell shock, but now this illness is referred to as post-traumatic stress disorder. Though it is now seen as a legitimate issue that should be dealt with compassionately, men who would run, panic or otherwise be rendered unable to hold a gun and fight were then considered to be cowards and were often executed by firing squad. In more modern times, countries such as Great Britain, France and Canada have granted official pardons to those who were executed for cowardice.