ASCLEPIADES OF BYTHINIA

(124-c. 40 BC)

   A classical physician and rhetorician from Prusa, Asia Minor, to whom the conceptual distinction between hallucinations and delusions has been attributed. The ancient Greeks referred to delusions and hallucinations by the single term phan-tasia (or visum, in Latin). It has been claimed that Asclepiades was the first to describe two varieties of phantasia, one in which the individual perceives an object, but interprets it as something else (i.e. what is known today as a delusion) and another in which the individual perceives an object although there is no object to perceive (i.e. what was designated later by Esquirol as a hallucination). However, it has been disputed whether the distinction put forward by Ascle-piades referred to hallucinations and delusions, or perhaps to hallucinations and " illusions. As Asclepiades's own writings have been lost, this issue may well remain unresolved. A definite solution is further complicated by the ambiguity of the term illusion itself, which is used to refer at once to the misperception of objects or stimuli in the external world and to the misinterpretation of (correctly perceived) objects or stimuli.

   References

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

   Zilboorg, G., Henry, G.W. (1941). A history of medical psychology. New York, NY: W.W. Norton & Company.