Also known as phantasm. The Greek noun phantasma means ghost or spectre. During the era of classic psychiatry, it had a variety of meanings and connotations. Thus it was used in 1826 by the German physiologist and zoologist Johannes Peter Müller (1801-1858) to denote the type of *complex visual hallucination now known as a *hypnagogic hallucination. As Müller recounts, he himself had experienced such phantasmata from childhood onwards. With closed eyes, especially in a dark environment, he was able to see colourful, three-dimensional scenes of persons, animals, landscapes, etc., as well as a gradual 'dawning' of the darkness in their background. As he explained, he was able to conjure up these hallucinations at will and to enjoy their continuously changing shapes for hours on end, at least as long as he was rested, and not preoccupied with other matters. And yet he noted that the content of these phantasms was beyond his conscious control. Without their being preceded by specks of light or other visual sensations that might act as a *point de repère and without reacting to any conscious efforts at steering in this or that direction, the phantasmata would appear spontaneously and display complex images which he was sure he had never seen before. In Müller's own words: "I sit there for quite a while with eyes closed; everything that I imagine is just imagination, imagined delineation within the dark visual field, without shining, without moving organically within the field of vision, when suddenly the moment of sympathy sets in between the fantastic and the light nerves, all of a sudden shining figures appear, without any effort of the imagination." According to Müller, phantasmata are quite common. Rather than relegating them to the class of * dreams or products of the imagination, he classifies them as actual perceptual phenomena attributable to the physiological workings of the perceptual system. In an era predating the functional and conceptual association of visual perception and the occipital cortex, Müller attributed their mediation to the Sehsinnsubstanz (i.e. 'substance of vision') located by him within the eye, and/or the cerebral structures connected to it, which he held responsible for mediating waking images as well as dream images. Müller also uses the term phantasma to denote a similarly complex type ofhallucination experienced in the auditory modality. The German psychiatrist Karl Ludwig Kahlbaum (1828-1899) used the term phantasma to denote a hallucination of the * centrifugal type. His compatriot Hermann Emminghaus (18451904) used it as an umbrella term for hallucinations and * illusions, while another compatriot, Georg Theodor Ziehen (1862-1950), used it to denote a hallucination that lacks the vividness of an ordinary sense perception.
References
Emminghaus, H. (1878). Allgemeine Psychopathologie, zur Einführung in das Studium der Geistesstörungen. Leipzig: F.C.W. Vogel.
Kahlbaum, K. (1866). Die Sinnesdelirien. Allgemeine Zeitschrift für Psychiatrie undpsychisch-gerichtliche Medizin, 23, 56-78.
Müller, J. (1826). Ueber die phantastischen Gesichtserscheinungen. Koblenz: Hölscher.
Ziehen, Th. (1911). Psychiatrie. Für Ärzte und Studierende bearbeitet. Vierte, vollständig umgearbeitete Auflage. Leipzig: Verlag von S. Hirzel.
Dictionary of Hallucinations. J.D. Blom. 2010.