Jewish mystical movements and the European ergot epidemics.

Chronic intake of ergot, a chemical present in bread blighted by ergot-producing fungi, results in a wide variety of neuropsychiatric and vascular symptoms. The symptomatology and epidemiology of outbreaks of ergot poisoning are traced, and are shown to coincide with the emergence of Jewish mystical movements, such as the early Pietist movement in Germany, Sabbateanism and Chasidism, thus suggesting that environmental ergotism contributed to these mystical movements. The interaction between ergotism and other nutritional, neuropsychiatric, social, psychological and historical influences is considered.