Demonism (synonymous with daemonomania = possession) denotes a peculiar state of mind characterized by the fact that certain psychic contents, the so-called complexes, take over the control of the total personality in place of the ego, at least temporarily, to such a degree that the free will of the ego is suspended.
In certain of these states ego-consciousness is present, in others it is eclipsed.
Demonism is a primordial psychic phenomenon and frequently occurs under primitive conditions. (Good descriptions in the New Testament, Luke 4:34, Mark 1:23, 5:2, etc.)
The phenomenon of demonism is not always spontaneous, but can also be deliberately induced as a “trance,” for instance in shamanism, spiritualism, etc. (Cf. J. Hastings, Encyclopaedia of Religion and Ethics; Schiirer. “Zur Vorstellung von der Besessenheit im Neuen Testament,” Jahrbuch fur protestantisehe Theologie, 1892.)
Medically, demonism belongs partly to the sphere of the psychogenic neuroses, partly to that of schizophrenia.
Demonism can also be epidemic. One of the most celebrated epidemics of the Middle Ages was the possession of the Ursulines of London, 1632.
The epidemic form includes the induced collective psychoses of a religious or political nature, such as those of the twentieth century. (Cf. G. le Bon, The Crowd, a Study of the Popular Mind, 1896; Otto Stoll, Suggestion und Hypnotismus in der Vbikerpsychologic, 2nd edn., 1904.) ~Carl Jung, “The Symbolic Life,” Page 648.