HISTORICAL PERSPECTIVE David Healy Margaret Harris Fiona Farquhar Stefanie Tschinkel Joanna Le Noury Historical overview: Kraepelin’s impact on psychiatry j Abstract This paper reviews the importance Emil Kraepelin put on disease course as a classificatory principle. It then outlines the academic reception of Kraepelin’s disease entities outside Germany, charts the uptake of his diagnostic concepts within clinical practice in Britain, and compares data on admissions for bipolar disorders, involutional melancholia and postpartum psychoses to the North Wales asylum during the period Kraepelin was working to data on contemporary admissions in an effort to shed further light on the validity of his diagnostic concepts. j Key words Kraepelin dementia praecox manic- depressive illness bipolar disorder Introduction This paper outlines Kraepelin’s use of disease course as a classificatory principle for the functional psy- choses and how this led to distinctions between dementia praecox and manic-depressive illness, with a particular reference to manic-depressive illness. Following from this, the paper explores the reception of Kraepelin’s thinking outside Germany, both how his ideas were broadly received, and how his diagnoses came to be used in clinical practice. Finally, the paper compares quantitative aspects of clinical presentations to mental health services both in Kraepelin’s day and now to flesh out some of the issues his thinking sought to resolve. This will focus on the comparative frequency of hospitalization for bipolar syndromes compared with other affective disorders, the relative rates of recovery of involutional melancholia compared to other melancholias, and the apparent contemporary decline in the frequency of de novo onset postpartum psychoses. j Disease course as a classificatory principle The drama in Kraepelin’s 1899 Textbook lies more in the emergence of dementia praecox, later schizo- phrenia, than it does in the appearance of manic- depressive insanity. In the 5th edition published in 1896, Kraepelin had maintained a separation between hebephrenia, catatonia and the paranoid psychoses, disorders introduced by Kahlbaum and Hecker, but in 1899 based on the new criterion of disease course he included hebephrenia, catatonia and a range of paranoid psychosis within dementia praecox. This new disease was characterized by its course, which was one of progressive dementia [9]. The notion of using disease course as a classifica- tory principle for mental disorders had emerged with Kahlbaum [10, 12]. Within the German speaking countries others, such as Meynert, put more weight on indicators of neurological abnormality. Yet others, such as Wernicke, argued for a localization of dis- turbed functions as the defining feature of disorders. No one argued for a classification system based pri- marily on disease course as Kraepelin did. Manic-depressive insanity had its place in the 1899 edition of the Textbook as a foil to dementia praecox, rather than as a worked out condition in its own right. In order to bring out the importance of disease course for his new system, Kraepelin had to have a con- trasting disorder that did not lead to cognitive and clinical decline. Manic-depressive disorder was that contrast, and as a consequence, almost by definition, affected patients had to get better, and almost any patients who had a disorder that got better had a variant of manic-depressive illness. In constructing the category of manic-depressive illness, Kraepelin took Kahlbaum’s circular insanity EAPCN 2003 D. Healy (&) M. Harris F. Farquhar S. Tschinkel J. Le Noury Cardiff University Department of Psychological Medicine Hergest Unit Ysbyly Gwynedd Bangor Gwynedd LL57 2PW, UK E-Mail: Healy_Hergest@compuserve.com Eur Arch Psychiatry Clin Neurosci (2008) 258 [Suppl 2]:18–24 DOI 10.1007/s00406-008-2003-4