[The beginning of Emil Kraepelin's classification of psychoses. A historical-methodological reflection on the occasion of the 100th anniversary of his "Heidelberg Address" 27 November 1898 on "nosologic dichotomy" of endogenous psychoses].

Emil Kraepelin's (1856-1926) famous lecture "Zur Diagnose und Prognose der Dementia praecox" was held in Heidelberg 100 years ago on 27. November 1889. In this lecture Kraepelin suggested for the first time his famous "nosological dichotomy" between the group of "manisch-depressives Irresein" and the so-called "Dementia-praecox-Gruppe". This dichotomy became world famous since the publication of his "Lehrbuch der Psychiatrie", 6th edition 1899. Kraepelin founded his psychiatric system on outcome observations and the nosological principles of Kahlbaum. His nosology is very influential to the present day. The revision of American psychiatry in the 1970's and 1980's is unthinkable without Kraepelin's concept. Therefore the name "Neo-Kraepelinianism" was created.