A group of  non-deteriorating, recurrent psychoses with full remission between episodes, which circle between two “poles”, as “manic-depressive psychosis” but in which the dominant psychopathology is  not “elated” and “melancholic” mood, as in “manic-depressive psychosis”, but in another area of mental pathology. The term without any qualifier was introduced, in 1928, by Karl Kleist. Prior to it, he referred to the same group of psychoses by various terms including “autochthonous constitutional psychoses”, “marginal degeneration psychoses”, “cycloid degeneration psychoses” (Kleist 1928; Shorter 2005; Teichmann 1990).

References
Kleist K. Über zykloide, paranoide und epileptoide  Psychosen und uber die Frage der Degenerationpsychosen. Schweiz Arch Neurol Neurochir Psychiat 1928; 23: 3-37

Shorter E, A Historical Dictionary of Psychiatry. Oxford/New York: Oxford University Press; 2005, pp. 300-3.

Teichmann G. The influence of Karl Kleist on the nosology of Karl Leonhard. Psychopathology 1990; 23: 267-76.

Thomas A. Ban
February 25, 2016