The following is an article from The Annals of Improbable Research.
A closer look at a medical research report
by Bertha Vanatian, AIR staff
Do shoes cause schizophrenia? Jarl Flensmark of Malmo wants to know, and in a recent paper in the journal Medical Hypotheses, he explains why.
“Heeled footwear,” he writes,” began to be used more than a 1000 years ago, and led to the occurrence of the first cases of schizophrenia. ... Industrialization of shoe production increased schizophrenia prevalence. Mechanization of the production started in Massachusetts, spread from there to England and Germany, and then to the rest of Western Europe. A remarkable increase in schizophrenia prevalence followed the same pattern.”
The story, if accurate and true, is disturbing. Flensmark sketches the details:
“The oldest depiction of a heeled shoe comes from Mesopotamia, and in this part of the world we also find the first institutions making provisions for mental disorders. ... In the beginning schizophrenia appears to be more common in the upper classes. Possible early victims were King Richard II and Henry VI of England, his grandfather Charles VI of France, his mother Jeanne de Bourbon, and his uncle Louis II de Bourbon, Erik XIV of Sweden, Juana of Castile [and] her grandmother Isabella of Portugal.” All of these individuals are either known or suspected of wearing heeled shoes.
He cites evidence from other parts of the world, too -- Turkey, Taiwan, the Balkans, Ireland, Italy, Ghana, Greenland, the Caribbean, and elsewhere.
“Probably the upper classes began using heeled footwear earlier than the lower classes,” Flensmark points out. He then cites studies from India and elsewhere, which seem to confirm that “schizophrenia first affects the upper classes.”