Psychopharmacology and the Classification of Functional Psychoses 

By Thomas A. Ban and Bertalan Pethö

Four-Dimensional Classification

Affective Psychoses

The origin of the concept of affective psychosis dates to the 1850s when Falret stated that a predictable "natural course" of an illness "presupposes the existence of a natural species of disease with a pattern of development." It was the application of this notion to the description of "natural species" ("endogenous") of disease, that presents with two specific cross-sectional psychopathological syndromes (i.e., manic and melancholic) and follows a predictable or "natural course" that led to the recognition of manic-depressive illness.

Falret (1864), in his lectures at Salpetriere (Lecons a l'Hospice de la Salpetriere) during 1850-1851, was first to describe folie circulair, the disorder later to become known as manic-depressive psychosis. In same year (1854) that Falret published his thesis De la folie circulaire, Baillarger (1854) presented the same concept, referring to it as folie a double forme, to the French Academy of Medicine. There has been some controversy regarding priority.