Psychosis: a history of the concept.

The history of the concept of psychosis is traced from the time it was coined in 1845 to the present day. Originally, psychosis included the category of mental handicap, as well as certain other serious mental disorders. But within a year, it had become synonymous with the two terms "psychopathy" and "psychoneurosis." Soon, all psychiatric disorders became subsumed under its umbrella heading amidst a confusing array of terminology. Psychosis is examined as it then became distinct from psychopathy and neurosis. Psychosis is discussed in terms of the following dichotomies: endogenous-exogenous psychoses, functional-organic psychoses, psychosis-neurosis, psychosis-psychopathy, and unitary-multiple psychoses. The way in which psychosis became a specialized term for serious mental disorders with a postulated organic etiology is outlined. The current status of the term and its future use are discussed.