- functional hallucination
- Historically the term functional hallucination has had a variety of meanings and connotations. The German expression funktionelle Hallucination was introduced in or shortly before 1866 by the German psychiatrist Karl Ludwig Kahlbaum (1828-1899). Kahlbaum used it to denote a hallucination prompted by a shift of attention towards a particular external object or stimulus, such as the picture of a deceased loved one, or the sound of footsteps coming down the hallway. Seeing that picture, or hearing those footsteps, the affected individual experiences a * vision depicting the beloved. Thus functional hallucinations as described by Kahlbaum are conceptually related to * reflex hallucinations and * synaesthesias. The term was used in a slightly different manner by the German psychiatrist and philosopher Karl Jaspers (1883-1969), as witness the following example. "A patient, for instance, hears voices while the water is running but they stop when the tap is turned off. He hears the running water and the voices simultaneously." According to Jaspers, voices of this particular kind should not be confused with * illusions, since "illusions contain an element of genuine perception [whereas] with functional hallucinations we have simultaneous hallucinations running alongside with a constant element of genuine sense-perception and disappearing at the same time as the sense-perception." The hallucinatory state described by Jaspers is also referred to as functional hallucinosis. A third use for the term functional hallucination is suggested by the American psychiatrist Gordon Forrer, who maintains that, "Functional hallucinations are sensory perceptions for which no physical cause can be assigned." For-rer sees an apt example ofa functional hallucination in * hallucinated pain, a type of pain which lacks the physical basis of tissue damage which it suggests, and yet is experienced in the form of a sensory percept. In Forrer's opinion, the central function of this type of functional hallucination is "its stimulus filling effect upon threatening or actual psychological emptiness." Thus, according to Forrer, subconsciously the affected individual would seem to prefer pain over a looming feeling of emptiness.ReferencesForrer, G.R. (1970). The function of hallucinated pain.In: Origin and mechanisms ofhallucina-tions. Proceedings of the 14th annual meeting ofthe Eastern Psychiatric Research Association held in New York City, November 14-15, 1969. EditedbyKeup,W.NewYork,NY: Plenum Press.Jaspers, K. (1997). Generalpsychopathology. Volume 1. Translated by Hoenig, J., Hamilton, M.W. Baltimore, MA: Johns Hopkins University Press.Kahlbaum, K. (1866). Die Sinnesdelirien. Allgemeine Zeitschrift für Psychiatrie und psychischgerichtliche Medizin, 23, 56-78.
Dictionary of Hallucinations. J.D. Blom. 2010.