Editing Emil Kraepelin (section)

== Theories and classification schemes ==
Kraepelin announced that he had found a new way of looking at mental illness, referring to the traditional view as "symptomatic" and to his view as "clinical". This turned out to be his [[paradigm]]-setting synthesis of the hundreds of mental disorders classified by the 19th century, grouping diseases together based on classification of [[syndrome]]—common ''patterns'' of symptoms over time—rather than by simple similarity of major symptoms in the manner of his predecessors.

Kraepelin described his work in the 5th edition of his textbook as a "decisive step from a symptomatic to a clinical view of insanity. . . . The importance of external clinical signs has . . . been subordinated to consideration of the conditions of origin, the course, and the terminus which result from individual disorders. Thus, all purely symptomatic categories have disappeared from the [[nosology]]".<ref name=decker/>

=== Psychosis and mood ===
Kraepelin is specifically credited with the classification of what was previously considered to be a [[Unitary psychosis|unitary concept of psychosis]], into two distinct forms (known as the [[Kraepelinian dichotomy]]):

* [[Bipolar disorder|manic depression]] (although commonly presented as synonym with bipolar disorder that is inaccurate; manic depressive illness encompasses a broader spectrum of mood disorders such as [[bipolar disorder]] and [[clinical depression|recurrent major depression]].<ref>{{cite journal | vauthors = Teodoro T, Durval R | title = Emil Kraepelin's taxonomic unitary view of manic-depressive insanity in the 21st century: the never-ending diagnostic conundrum of bipolar depression | journal = CNS Spectrums | date = October 2022 | volume = 28 | issue = 4 | pages = 389–390 | pmid = 36210529 | doi = 10.1017/s109285292200102x| s2cid = 252779392 | doi-access = free }}</ref>
* [[dementia praecox]].

Drawing on his long-term research, and using the criteria of course, outcome and [[prognosis]], he developed the concept of [[dementia praecox]], which he defined as the "sub-acute development of a peculiar simple condition of mental weakness occurring at a youthful age".  When he first introduced this concept as a diagnostic entity in the fourth German edition of his ''Lehrbuch der Psychiatrie'' in 1893, it was placed among the degenerative disorders alongside, but separate from, [[catatonia]] and [[dementia paranoides]]. At that time, the concept corresponded by and large with [[Ewald Hecker]]'s [[hebephrenia]]. In the sixth edition of the ''Lehrbuch'' in 1899 all three of these clinical types are treated as different expressions of one disease, dementia praecox.<ref>{{cite web|last=Yuhas|first=Daisy|title=Throughout History, Defining Schizophrenia Has Remained a Challenge (Timeline)|date=March 2013 |url=http://www.scientificamerican.com/article.cfm?id=throughout-history-defining-schizophrenia-has-remained-challenge|publisher=Scientific American Mind (March 2013)|access-date=2 March 2013}}.</ref>

One of the cardinal principles of his method was the recognition that any given symptom may appear in virtually any one of these disorders; e.g., there is almost no single symptom occurring in dementia praecox which cannot sometimes be found in manic depression. What distinguishes each disease symptomatically (as opposed to the underlying [[pathology]]) is not any particular ([[pathognomonic]]) symptom or symptoms, but a specific pattern of symptoms. In the absence of a direct physiological or genetic test or marker for each disease, it is only possible to distinguish them by their specific pattern of symptoms. Thus, Kraepelin's system is a method for pattern recognition, not grouping by common symptoms.

It has been claimed that Kraepelin also demonstrated specific patterns in the genetics of these disorders and patterns in their course and outcome,<ref>{{cite journal|last1=Ebert|first1=Andreas|title=Emil Kraepelin: A pioneer of scientific understanding of psychiatry and psychopharmacology|journal=Indian Journal of Psychiatry|pmc=2927892|pmid=20838510|doi=10.4103/0019-5545.64591|volume=52|issue=2|pages=191–2|year=2010 |doi-access=free }}</ref> but no specific [[biomarkers]] have yet been identified. Generally speaking, there tend to be more people with schizophrenia among the relatives of schizophrenic patients than in the general population, while manic depression is more frequent in the relatives of manic depressives. Though, of course, this does not demonstrate genetic linkage, as this might be a [[social|socio]]-[[Environmental psychology|environmental]] factor as well.

He also reported a pattern to the course and outcome of these conditions. Kraepelin believed that schizophrenia had a deteriorating course in which mental function continuously (although perhaps erratically) declines, while manic-depressive patients experienced a course of illness which was intermittent, where patients were relatively symptom-free during the intervals which separate acute episodes. This led Kraepelin to name what we now know as schizophrenia, dementia praecox (the [[dementia]] part signifying the irreversible mental decline). It later became clear that dementia praecox did not necessarily lead to mental decline and was thus renamed [[schizophrenia]] by [[Eugen Bleuler]] to correct Kraepelin's misnomer.

In addition, as Kraepelin accepted in 1920, "It is becoming increasingly obvious that we cannot satisfactorily distinguish these two diseases"; however, he maintained that "On the one hand we find those patients with irreversible dementia and severe cortical lesions. On the other are those patients whose personality remains intact".<ref>{{cite journal |vauthors=Berrios GE, Luque R, Villagran JM| year = 2003 | title = Schizophrenia: a conceptual history | url = http://www.ijpsy.com/volumen3/num2/60/schizophrenia-a-conceptual-history-esquizofrenia-EN.pdf | journal = International Journal of Psychology and Psychological Therapy | volume = 3 | issue = 2| pages = 111–140 }}</ref> Nevertheless, overlap between the diagnoses and neurological abnormalities (when found) have continued, and in fact a diagnostic category of [[schizoaffective disorder]] would be brought in to cover the intermediate cases.

Kraepelin devoted very few pages to his speculations about the etiology of his two major insanities, dementia praecox and manic-depressive insanity. However, from 1896 to his death in 1926 he held to the speculation that these insanities (particularly dementia praecox) would one day probably be found to be caused by a gradual systemic or "whole body" disease process, probably [[metabolic]], which affected many of the organs and nerves in the body but affected the brain in a final, decisive cascade.<ref>{{cite magazine|last=Noll|first=Richard|title=Whole Body Madness|url=http://www.psychiatrictimes.com/display/article/10168/2104852|magazine=Psychiatric Times|access-date=26 September 2012}}.</ref>

=== Psychopathic personalities ===
In the first through sixth edition of Kraepelin's influential psychiatry textbook, there was a section on [[moral insanity]], which meant then a disorder of the emotions or moral sense without apparent delusions or hallucinations, and which Kraepelin defined as "lack or weakness of those sentiments which counter the ruthless satisfaction of egotism". He attributed this mainly to degeneration. This has been described as a psychiatric redefinition of [[Cesare Lombroso]]'s theories of the "born criminal", conceptualised as a "[[moral]] defect", though Kraepelin stressed it was not yet possible to recognise them by physical characteristics.<ref name=Wetzell2000>[[Richard Wetzell]] (2000) [https://books.google.com/books?id=iGW7QLJmuwoC Inventing the criminal: a history of German criminology, 1880–1945] from p 59 & 146, misc.</ref>

In fact from 1904 Kraepelin changed the section heading to "The born criminal", moving it from under "Congenital feeble-mindedness" to a new chapter on "Psychopathic personalities". They were treated under a theory of degeneration. Four types were distinguished: born criminals (inborn delinquents), [[pathological liars]], [[querulous]] persons, and Triebmenschen (persons driven by a basic compulsion, including [[Vagabond (person)|vagabonds]], [[spendthrifts]], and [[dipsomaniacs]]).

The concept of "[[psychopathic]] inferiorities" had been recently popularised in Germany by [[Julius Ludwig August Koch]], who proposed congenital and acquired types. Kraepelin had no evidence or explanation suggesting a congenital cause, and his assumption therefore appears to have been simple "[[biologism]]". Others, such as [[Gustav Aschaffenburg]], argued for a varying combination of causes. Kraepelin's assumption of a moral defect rather than a positive drive towards crime has also been questioned, as it implies that the moral sense is somehow inborn and unvarying, yet it was known to vary by time and place, and Kraepelin never considered that the moral sense might just be different.

[[Kurt Schneider]] criticized Kraepelin's nosology on topics such as [[Haltlose]] for appearing to be a list of behaviors that he considered undesirable, rather than medical conditions, though Schneider's alternative version has also been criticised on the same basis. Nevertheless, many essentials of these diagnostic systems were introduced into the diagnostic systems, and remarkable similarities remain in the DSM-5 and ICD-10.<ref name=Wetzell2000/> The issues would today mainly be considered under the category of [[personality disorders]], or in terms of Kraepelin's focus on [[psychopathy]].

Kraepelin had referred to psychopathic conditions (or "states") in his 1896 edition, including compulsive insanity, impulsive insanity, [[homosexuality]], and mood disturbances. From 1904, however, he instead termed those "original disease conditions, and introduced the new alternative category of psychopathic personalities. In the eighth edition from 1909 that category would include, in addition to a separate "dissocial" type, the excitable, the unstable, the Triebmenschen driven persons, eccentrics, the liars and swindlers, and the quarrelsome. It has been described as remarkable that Kraepelin now considered mood disturbances to be not part of the same category, but only attenuated (more mild) phases of manic depressive illness; this corresponds to current classification schemes.<ref>Henning Sass & Alan Felthous (2008) Chapter 1: History and Conceptual Development of Psychopathic Disorders in [https://books.google.com/books?id=8WhcGo-1MkYC International Handbook on Psychopathic Disorders and the Law]. Edited by Alan Felthous, Henning Sass.</ref>

=== Alzheimer's disease ===
Kraepelin postulated that there is a specific brain or other biological pathology underlying each of the major psychiatric disorders.<ref>{{Cite journal |last1=Ebert |first1=Andreas |last2=Bär |first2=Karl-Jürgen |date=2010 |title=Emil Kraepelin: A pioneer of scientific understanding of psychiatry and psychopharmacology |journal=Indian Journal of Psychiatry |volume=52 |issue=2 |pages=191–192 |doi=10.4103/0019-5545.64591 |doi-access=free |issn=0019-5545 |pmc=2927892 |pmid=20838510}}</ref> As a colleague of [[Alois Alzheimer]], he was a co-discoverer of [[Alzheimer's disease]], and his laboratory discovered its pathological basis. Kraepelin was confident that it would someday be possible to identify the pathological basis of each of the major psychiatric disorders.{{citation needed|date=March 2013}}

=== Eugenics ===
{{Eugenics sidebar|pre-war academics}}
Upon moving to become Professor of Clinical Psychiatry at the [[University of Munich]] in 1903, Kraepelin increasingly wrote on social policy issues. He was a strong and influential proponent of [[eugenics]] and [[racial hygiene]]. His publications included a focus on [[alcoholism]], [[crime]], [[Social degeneration|degeneration]] and [[hysteria]].<ref name=Engstrom2007>{{cite journal|last=Engstrom |first=E. J. |title=On the Question of Degeneration' by Emil Kraepelin (1908)1 |journal=[[History of Psychiatry (journal)|History of Psychiatry]] |date=1 September 2007 |volume=18 |issue=3 |pages=389–398 |doi=10.1177/0957154X07079689 |pmid=18175639 |s2cid=46482747 |url=http://134.76.163.171:8080/jspui/bitstream/123456789/10898/1/PEER_stage2_10.1177%252F0957154X07079689.pdf |url-status=dead |archive-url=https://web.archive.org/web/20130526013902/http://134.76.163.171:8080/jspui/bitstream/123456789/10898/1/PEER_stage2_10.1177%252F0957154X07079689.pdf |archive-date=26 May 2013}}.</ref>

Kraepelin was convinced that such institutions as the [[education system]] and the [[welfare state]], because of their trend to break the processes of [[natural selection]], undermined the Germans' biological "struggle for survival".<ref name=Engstrom2006/> He was concerned to preserve and enhance the German people, the [[Volk]], in the sense of nation or race. He appears to have held [[Lamarckian]] concepts of evolution, such that cultural deterioration could be inherited. He was a strong ally and promoter of the work of fellow psychiatrist (and pupil and later successor as director of the clinic) [[Ernst Rüdin]] to clarify the mechanisms of genetic inheritance as to make a so-called "[[empirical]] genetic [[prognosis]]".<ref name=Engstrom2007/>

Martin Brune has pointed out that Kraepelin and Rüdin also appear to have been ardent advocates of a [[self-domestication]] theory, a version of [[social Darwinism]] which held that modern culture was not allowing people to be weeded out, resulting in more mental disorder and deterioration of the gene pool. Kraepelin saw a number of "symptoms" of this, such as "weakening of viability and resistance, decreasing fertility, proletarianisation, and moral damage due to "penning up people" [''Zusammenpferchung'']. He also wrote that "the number of idiots, epileptics, psychopaths, criminals, prostitutes, and tramps who descend from alcoholic and syphilitic parents, and who transfer their inferiority to their offspring, is incalculable". He felt that "the well-known example of the [[Jews]], with their strong disposition towards nervous and mental disorders, teaches us that their extraordinarily advanced domestication may eventually imprint clear marks on the race". Brune states that Kraepelin's [[nosological]] system "was, to a great deal, built on the degeneration [[paradigm]]".<ref>{{cite journal|last=Brüne|first=Martin|title=On human self-domestication, psychiatry, and eugenics|journal=Philosophy, Ethics, and Humanities in Medicine|date=1 January 2007|volume=2|issue=1|pages=21|doi=10.1186/1747-5341-2-21|pmid=17919321|pmc=2082022 |doi-access=free }}</ref>