EPIDEMIC HALLUCINATION

   Also known as popular hallucination and mass hallucinosis. All three terms are used to denote a hallucination shared by a relatively large number of people, who typically believe the content of the hallucination in question to be "veridical or at least "coincidental in nature. The French alienist Alexandre Jacques François Brierre de Boismont (1797-1881) gives the following examples, derived from the work of the French chronicler and physician Rigord (c. 1150-c. 1209): "On the day Saladin entered the Holy City, says Rigord, the monks of Argenteuil saw the moon descend from heaven upon earth, and then re-ascend to heaven.In many churches the crucifixes and images of the saints shed tears of blood in the presence of the faithful... These examples, which we have selected from many others related by the same writer, clearly prove that hallucinations may affect a number of persons at the same time, without there being any reason to accuse them of insanity." In biomedicine the mediation of epidemic hallucinations is associated primarily with phenomena such as mass hysteria and mass hypnosis. Paranormal and religious explanations for the working mechanism of epidemic hallucinations typically range from telepathy to divine intervention. The German hallucinations researcher Edmund Parish (18611916) distinguishes the epidemic hallucination from the " collective hallucination, reserving the latter term for a type of hallucination in which a limited number of people are under the impression that they share a common hallucinatory percept.

   References

   Brierre de Boismont, A. (1859). On hallucinations. A history and explanation of apparitions, visions, dreams, ecstasy, magnetism, and somnambulism. Translated by Hulme, R.T. London: Henry Renshaw

   Critchley, M. (1939). Visual and auditory hallucinations. British Medical Journal, 2, 634-639.

   Parish, E. (1897). Hallucinations and illusions. A study ofthe fallacies ofperception. London: Walter Scott.