title: ["This time the reviewer is proud and pleased to agree with Kraepelin's latest nosology, since it is his own"].
abstract: This paper aims to acknowledge the major impact Leipzig neurologist and psychiatrist Paul Julius Möbius had on the classification of nervous and mental illnesses. His main objective was to differentiate them by their underlying cause. Between 1890 and 1893 he sampled his views for both subjects. Expanding Evariste Marandon de Montyel's ideas of 1889 Möbius not only agreed that illnesses can emerge from causes that lie mainly within the body as well as mainly outside it, he even went as far as to say that there were illnesses that are solely based on causes outside the body. Moreover, it was Möbius who first introduced the terms "endogenous" and "exogenous" diseases. In accordance with the degeneration theory of his time he referred to transmission as the only etiological factor for endogenous illnesses, proposing that the extent of the illness is determined by the degree of degeneration. In the case of exogenous illnesses, however, the various stimuli affecting the nervous system would lead to qualitatively different illnesses. It is mainly due to Emil Kraepelin, who took over Möbius's dichotomy in the fifth edition of his most influential textbook of psychiatry of 1896, that his views had a lasting influence. And as it shown in the present study it was both through personal arguments with his old friend from Leipzig as well as through Möbius's equally critical and reprimanding reviews of the individual editions of Kraepelin's textbook that the latter acknowledged the importance of the etiological factor in his multi-factorial clinical and empirical nosology. However, since Möbius only considered etiological causes and neglected all others one should refrain from renaming, as suggested, "Kraepelin's nosology" as "Kraepelin's and Möbius's classification".
authors.affiliation: Archiv für Leipziger Psychiatriegeschichte, Klinik und Poliklinik für Psychiatrie Universität Leipzig. steinbh@medizin.uni-leipzig.de
authors.forename: H
authors.initials: H
authors.lastname: Steinberg
mesh_terms: D049672:History, 19th Century; D049673:History, 20th Century; D006801:Humans; D001523:Mental Disorders / Q000145:classification* / Q000209:etiology / Q000266:history*; D009422:Nervous System Diseases / Q000145:classification* / Q000209:etiology / Q000266:history*; D011570:Psychiatry / Q000266:history*