Causes of the Great Depression
Second, there are the monetarists, who believe that the Great Depression started as an ordinary recession, but that significant policy mistakes by monetary authorities (especially the Federal Reserve) caused a shrinking of the money supply which greatly exacerbated the economic situation, causing a recession to descend into the Great Depression. Related to this explanation are those who point to debt deflation causing those who borrow to owe ever more in real terms.
Causes of the Great Depression
Beginning late in the 1920s, European demand for U.S. goods began to decline. That was partly because European industry and agriculture were becoming more productive, and partly because some European nations (most notably Weimar Germany) were suffering serious financial crises and could not afford to buy goods overseas. However, the central issue causing the destabilization of the European economy in the late 1920s was the international debt structure that had emerged in the aftermath of World War I.