Zero stroke or cipher stroke was a mental disorder, reportedly
diagnosed by physicians in Germany under the Weimar Republic and
said to be caused by hyperinflation of the early 1920s. The
disorder was primarily characterized by the desire of patients
to write endless rows of zeros, which are also referred to as
ciphers. After the Treaty of Versailles, which formally ended
World War I in 1919, Germany faced a damaged economy and a
requirement to pay immense war reparations to the Allies. At the
beginning of 1921, the German currency was relatively stable at
about 60 Marks per US Dollar, but inflation rapidly increased
after August 1921, and the Mark fell to less than one third of a
cent by November 1921 (approx. 330 Marks per US Dollar). The
Mark stabilized again at the beginning of 1922, but when there
was no resolution to the reparations problem the inflation
changed to hyperinflation and the Mark fell to 8000 Marks per
Dollar by December 1922. The inflation reached its peak by
November 1923 when a new curre