hallucination

   Formerly known as hallucinatio, allucinatio, alucinatio, * alusia, * fallacia, * idolum, and *phantasma. Hallucination can be defined as a percept, experienced by a waking individual, in the absence of an appropriate stimulus from the extracorporeal world. The term hallucination comes from the Latin verb *halucinari (also written as * alucinari), which means to wander mentally or to be absent-minded. It has its root in the Greek verb aluein, which means to wander or to be distraught. Originally neither of these classical terms had a connotation of perceptual disturbance. The term phantasia was employed to designate what are today known as hallucinations and delusions. The person traditionally credited with making a conceptual distinction between hallucinations and delusions avant la lettre is the classical physician and rhetorician Asclepiades (124-c.40 B.C.). The term hallucination probably came into use during the first century AD. It entered the English language in 1572 via the translated work of the Swiss theologian Ludwig Lavater (1527-1586), and English medical jargon in 1798 through the work of the Scottish physician Alexander Crichton (1763-1846). Lavater used the term hallucination to connote "Ghostes and spirites walking by nyght, and strange noyses, crackes, and sundry forwarnynges, whiche commonly happen before the death of menne, great slaughters and alterations of Kyngdomes". Since Lavater's time the meaning of the term hallucination has varied considerably among different authors until the first half of the 19th century. It was used by the Swiss anatomist and alienist Felix Plater (1536-1614) to denote mental illness in general, whereas the French physician François Boissier de Sauvages (1706-1767) employed it as an umbrella term for perceptual errors caused by malfunctioning of the senses, comprising such diverse conditions as *tinnitus, *diplopia, vertigo, hypochondriasis, and somnambulism. The British experimentalist David Ferrier (1843-1928) used the term hallucination to designate deceptive impressions ranging from *muscae volitantes to the most terrifying * phantoms. And the above-mentioned Crichton used the term to cover both hallucinations and *illusions as we know them today. Interestingly, the British physician Samuel Hibbert (1782-1848) defined hallucinations as ideas that outstrip regular sense impressions as regards their vividness. As he maintained, "Hallucinations are nothing more than ideas, or the recollected images of the mind, which have been rendered more vivid than actual impressions". The historical watershed in the usage of the term hallucination stems from a contribution of the then 45-year-old French alienist Jean-Etienne Dominique Esquirol (1772-1840) to the French Dictionary ofthe Medical Sciences. In that work, published in 1817, Esquirol gave the following characterization of hallucinations. "A mad person who has the thorough conviction of an actually perceived sensation, while no object suited to excite that sensation is present within the range of his senses, abides in a state of hallucination. He is a visionary." In 1838, after having made some adjustments to this characterization, Esquirol stated that "A person is said to labour under a hallucination, or to be a visionary, who has a thorough conviction of the perception of a sensation, when no external object, suited to excite this sensation, has impressed the senses." An important reason for Esquirol to define the term in this way was his wish to have a single name at his disposal for * sensory deceptions that might occur in any of the sensory modalities. As he wrote, "Hallucinations of sight... have been denominated visions. This name is suited to a single form of hallucination. Who would dare to say, visions of hearing, visions of taste, visions of smell? (...)

   A generic term is wanting. I have proposed the term hallucination, as having determinate signification, and as adapted consequently, to all the varieties of delirium which suppose the presence of an object proper to excite one of the senses, although these objects may be beyond their reach." Thus Esquirol added a specific connotation to the term hallucination which has remained largely in force to the present day. However, to place this observation in the proper light it should be noted that Esquirol was not the first person in history to define hallucinations as percepts without an appropriate substratum in the external world. As pointed out by the French asylum physician Raoul Mourgue, quite similar definitions had previously been formulated by such authors as Nicolas Malebranche (1638-1715), Herman Boerhaave (1668-1738), Charles Bonnet (1720-1792), Immanuel Kant (1724-1804), and Erasmus Darwin (1731-1802). Thus it would be more appropriate to stress Esquirol's part in safeguarding the classical doctrine of hallucinations as opposed to actually formulating it. Moreover, following Esquirol's groundbreaking work the term hallucination - although given a somewhat tighter definition - continues to have multiple connotations.

   References

   Crichton, A. (1798). An inquiry into thenatureand origin ofmental derangement. London: Cadell, Junior, and Davies.

   Esquirol, E. (1817). Hallucination.In: Dictionnaire des sciences médicales par une société de médecins et de chirurgiens, Vol. XX.Edited by Adelon et al. Paris: Panckoucke.

   Esquirol, J.-E.D. (1965). Mental maladies. A treatise on insanity. A facsimile of the English edition of 1845. Translated by Hunt, E.K. New York, NY: Hafner Publishing Company.

   Lavater, L. (1572). Of ghostes andspirites walking by nyght. Translated by Harrison, R. London: Watkyns.

   Mourgue, R. (1932). Neurobiologie de l'hallucination. Essai sur une variété particulière de désintégration de la fonction. Bruxelles: Maurice Lamertin.

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

   Sarbin, T.R., Juhasz, J.B. (1967). The historical background of the concept of hallucination. Journal of the History ofthe Behavioural Sciences, 5, 339-358.

   Stone, M.H. (1997). Healing the mind. A history of Psychiatry from antiquity to the present. New York, NY: W.W. Norton & Company.