I understand "old Europe" a little better after reading The Living Unknown Soldier by Jean-Yves Le Naour, translated from the French by Penny Allen. Le Naour writes the story of Anthelme Mangin, an amnesiac POW during the First World War, repatriated back to France by the Germans, and than the subject of a twenty-year long court battle by families claiming him as their son, or father, or husband.
A staggering 500,000 French MIAs at the end of the war. The amazon links describe the story.
Interesting to read example of early psychiatric care at work. The Doctors deliberately infected Mangin to induce a fever and question a delirious Mangin in hope of recalling memories (it worked).
Mangin died in 1942 probably from malnutrition caused by food shortages in Asylums during the German occupation.