Ernst Rüdin: The Founding Father of Psychiatric Genetics

In a 2013 edition of the Journal of the History of Biology, Norbert Wetzel and I published an article on the Swiss-German psychiatric geneticist Ernst Rüdin (1874-1952) and his close colleagues, and how their work and crimes in the Nazi era have been discussed or ignored by contemporary psychiatric genetic writers and researchers.¹ Here I would like to summarize the main points we raised in that article, and to make several additional observations.

After immigrating to Germany (Bavaria), Rüdin became the founder of the psychiatric genetics field and was also a founder of the German racial hygiene movement. Throughout his long career he played a major role in promoting eugenic ideas and policies in Germany, including helping formulate the 1933 Nazi eugenic sterilization law and other governmental policies. In the early 1940s, Rüdin supported the killing of children and mental patients under a Nazi program euphemistically called “euthanasia.”

Psychiatric Genetics and Racial Hygiene

Alfred Ploetz and Rüdin were among the founders of the German Society for Racial Hygiene (Gesellschaft für Rassenhygiene) in 1905. The aims of the German racial hygiene movement, similar to eugenics organizations in other countries, were to promote the reproduction of the “genetically fit,” and to eradicate “undesirable” traits in the population. Racial hygienists argued that psychiatric disorders, and traits such as criminality, alcoholism, and “feeble-mindedness” (angeborener Schwachsinn), were caused mainly by hereditary factors.

Long before the Nazi seizure of power in 1933, Rüdin and his racial hygienics colleagues, which included twin method developer Hermann W. Siemens, were tireless advocates of programs targeting people who they saw as the dangerous carriers of “hereditary taint ” (erbliche Belastung).² Lacking any family studies, twin studies, adoption studies, or gene discoveries, Rüdin called for the sterilization of chronic alcoholics as early as 1903, which as a historian put it, “marked the beginning of a life-long crusade for sterilization of the degenerate.”³ Rüdin also wrote in 1903 that in order to obtain “biologically fit members of the race,” it would be necessary to promote “maximum propagation of those who are healthy, robust and . . . ethically superior,” while preventing “the weak, ill, unfit, and morally reprehensible from reproduction by artificial selection, . . . by instruction and by private and government force.”⁴ Before the passage of compulsory eugenic sterilization laws anywhere in the world, the 29-year-old Rüdin already was calling for the use of “private and government force” to curb the reproduction of the “unfit,” in order to prevent what racial hygienists feared was the future genetic “degeneration” of the German people.

Three decades later, soon after the Nazis took power in early 1933, Rüdin and his close psychiatric genetics associates at the Genealogic-Demographic Department of the German Research Institute for Psychiatry in Munich, such as Hans Luxenburger and Bruno Schulz, played a major role in implementing and justifying the 1933 German “Law for the Prevention of Genetically Diseased Offspring” (Gesetz zur Verhütung erbkranken Nachwuchses).⁵ Luxenburger had performed and published the first psychiatric genetic twin study in 1928, and was a leading advocate of eugenic policies in the late-Weimar (pre-Hitler) period and after.⁶

The 1933 law provided for the compulsory eugenic surgical sterilization of people diagnosed with “genetic” conditions such as feeble-mindedness, schizophrenia, manic-depressive insanity, genetic epilepsy, Huntington’s chorea, genetic blindness or deafness, or severe alcoholism. Rüdin co-authored the official commentary summarizing the alleged scientific justification for the law.⁷ The law created a massive program of compulsory eugenic sterilization and led to the establishment of roughly 1,700 “hereditary health courts” (Erbgesundheitsgerichte) throughout Germany, and resulted in the forcible sterilization of roughly 400,000 Germans between 1934 and 1939, primarily on the basis of being labeled “feeble-minded” or “schizophrenic.” About 6,000 people died as a direct result of the surgical procedure.⁸

In 1934 Rüdin wrote that “only through the political work of Adolf Hitler, and only through him has our more than thirty-year-old dream become reality: to be able to put race hygiene into action.”⁹ In 1935, Rüdin called for the “widening of the spectrum of diseases necessitating sterilization” to include “valueless individuals . . . all who were socially inferior psychopaths on account of moral confusion or severe ethical defects,” and “the great mass of serious and incorrigible constitutional criminals.”¹⁰ Prior to the advent of the National Socialist state, however, Rüdin had often supported only voluntary sterilization. In an English language article entitled “Eugenic Sterilization: An Urgent Need,” published in the April, 1933 edition of the American journal Birth Control Review (but likely submitted for publication before Hitler’s rise to power), Rüdin wrote, “There is absolutely no question of using compulsion. Whether in the far future something of the sort might be required cannot be predicted now.”¹¹ Previously, in a paper delivered to the 1930 First International Congress on Mental Hygiene, Rüdin had supported the use of “voluntary sterilization” as the “most suitable measure” in support of eugenic policies.¹²

Rüdin received numerous awards for his work in the Nazi era, including the prestigious Goethe Medal of Arts and Sciences in 1939 from the Reich Ministry of the Interior. In 1944, Rüdin received the “Adlerschild des Deutschen Reiches” medal (Eagle Shield of the German Reich) bearing the Nazi eagle from Hitler, and was praised as being a “pathfinder in the field of hereditary hygiene.”¹³

After the Nazi seizure of power, researchers and students from various European countries came to Munich to study under Rüdin and his associates at the Genealogical-Demographic Department. David Rosenthal, a leading American psychiatric geneticist and an admirer of Rüdin’s scientific work, wrote in 1971, “From this institute emerged all of the pioneering psychiatric geneticists.”¹⁴ Among these were several people who subsequently had long and influential careers in psychiatry and psychiatric genetics, such as Franz Kallmann (Germany and the United States), Eliot Slater (UK), Eric Strömgren (Denmark), and Erik Essen-Möller (Sweden). These researchers went on to train the next generation of psychiatric geneticists.

Psychiatric Genetics Then and Now: Based on Bad Science

The psychiatric genetics field grew rapidly in the 1930s, but suffered greatly after World War II in the wake of revelations about the Holocaust and the complicity of German scientists in the Nazi’s crimes against humanity in the name of eugenics and racial hygiene. The mid 1940s through the late 1960s were lean years for the field, with a relatively small group of researchers and their students operating in various countries. Psychiatric genetics began a comeback in the late 1960s on the basis of new adoption studies and a greater acceptance of twin studies, and the first annual Psychiatric Genetic Word Congress took place in 1993. The XXIII^rd World Congress of Psychiatric Genetics was held in Toronto in October, 2015.

The main statistical product of Munich school research was the “empirical genetic prognosis” (empirische Erbprognose), which involved calculating the probability that (presumably hereditary) psychiatric disorders would eventually appear in the biological relatives and descendants of people diagnosed with these disorders. These calculations, which were based mainly on family studies and family pedigree diagrams, produced age-corrected “morbidity risk” (MR) percentage figures for various groups of relatives biologically related to the diagnosed “proband.” Much of the work of Rüdin, Luxenburger, Schulz and their psychiatric genetic colleagues in the Nazi era involved calculating morbidity risk estimates in the service of the sterilization law and other racial hygienic measures, even though it is now widely recognized—even by most psychiatric geneticists—that behavioral characteristics can “run in the family” for non-genetic reasons.¹⁵

Although contemporary psychiatric genetic researchers reject eugenic ideas and programs (while promoting genetic counseling), their claims that hereditary factors play an important role in causing psychiatric disorders are as wrong today as they were in Rüdin’s era.¹⁶ Rüdin’s psychiatric genetics was based its leaders’ strong pre-existing beliefs in the importance of heredity and the dangers this posed to society—beliefs that were “supported” by pseudoscientific kinship study methods such as twin studies, and genetically-interpreted family studies and family pedigree diagrams. Current psychiatric genetic theories and claims are based on kinship studies of families, twins, and adoptees, and claims that genes for some psychiatric disorders have been identified. However, psychiatric kinship studies are subject to massive flaws and biases, and are based on clearly false assumptions.¹⁷ In addition, despite recent assertions, attempts to replicate gene finding claims have failed. As a leading behavioral genetic researcher recognized in the fall of 2015, “Scientists have not identified a single gene that would meet any reasonable standard as a ‘gene for’ schizophrenia, intelligence, depression, or extraversion.”¹⁸

In other words, although a focus on eugenics and the perceived danger of degeneration is absent from modern psychiatric genetics, the pseudoscientific bases of its claims remain in place.

In the very unlikely case that predisposing genes for psychiatric disorders are eventually identified, environmental factors, which are changeable, could still be the main focus of social and research attention. Indeed, although the great majority of people labeled “schizophrenic” in Nazi Germany tragically and criminally were either sterilized or killed, postwar studies show a high incidence rate of new schizophrenia cases in Germany.¹⁹

A 1938 Article

In a 1938 edition of Archiv für Rassen- und Gesellschaftsbiologie (Archive for Racial and Social Biology), Ploetz and Rüdin published an article entitled “On the Development of the German Reich since our Führer’s Takeover of Power on January 30, 1933.”²⁰ This article, which was “addressed mainly to our foreign readers,” outlined what Ploetz and Rüdin saw as the main achievements of psychiatric genetics, racial hygiene, and the Nazi regime. They described compulsory eugenic sterilization, the Nuremberg laws, and the vicious repression of “the Jewish part of the population” as scientific policies which they proudly played a role in helping implement.

In this article, Ploetz and Rüdin reviewed “the most important advances…in our field of racial and social biology as well as racial and social hygiene, a field that was designated by Adolf Hitler as the most important foundation of our life as a people and a state.” They praised the 1933 sterilization law, and also the 1935 Nuremburg Law for the Protection of German Blood and German Honor, where they reported that “marriages or extramarital sexual intercourse between Jews and citizens with German or related blood were banned.” Ploetz and Rüdin believed that these and other such laws produced “streams of beneficial effects, effects that will only unfold in their full power in the near and especially in the distant future.”

They informed their readers, approvingly, that the “Jewish part of the population that once had such strong influence, and even dominated our cultural and political life, has been strongly forced back, for example in the military, in the economy, among professional judges, among teachers of all kinds and levels, in the media, in theater, in film.”

After praising German militarism and Hitler’s foreign policy moves, which included the then-recent occupation of Austria (the Anschluss), Ploetz and Rüdin concluded,

“These are some of the main parts of the giant work of our Führer and his loyal supporters! Hitler moves through his deeds into the rank of our greatest leaders since ancient times! Our nation has understood this and is devoted to him with grateful hearts. No German prince, no German king or emperor has ever been loved so passionately by his entire people as Adolf Hitler.”

Rüdin and “Euthanasia”

In the late 1930s, at the outset of World War II, the Nazi regime took eugenic sterilization to its logical conclusion and instituted a secret plan to kill mental patients and other “defectives,” “useless eaters,” and “incurables.” This program, code named “T4” and referred to by the authorities as “euthanasia,” led to the murder of 70,000 people by gas, lethal injection, starvation, and other methods in the first phase between 1939 and 1941 under the direction of the government and leading doctors and psychiatrists.²¹ Over 100,000 more people were killed between 1939 and 1945 in further actions in Germany and the occupied territories. As Sheila Faith Weiss put it in her important 2010 book The Nazi Symbiosis, “the word ‘euthanasia’…was a Nazi euphemism to describe the systematic slaughter of perhaps more than two hundred thousand individuals in Greater Germany and Poland by gas, lethal injections, medication, or outright planned starvation.”²² (Chapter 3 of Weiss’s book, entitled “The Munich Pact,” contains an excellent detailed review of the activities of Rüdin and his Munich colleagues.)

Although there is little evidence that Rüdin played a major role in initiating the “euthanasia” killing program, it is beyond question that he participated in and helped implement it.²³ According to Rüdin’s biographer Matthias Weber, in internal memorandums Rüdin discussed “euthanasia” as a type of “therapeutic reform.”²⁴ Rüdin wrote in 1942 about the eugenic importance of “distinguishing which children could, already as children, be clearly categorized as so valueless and worthy of elimination that…they could be recommended for euthanasia in their own interest and that of the German people.”²⁵

German historian Volker Roelcke documented Rüdin’s support to the killing of children at the Psychiatric Department of the University of Heidelberg in 1943-45.²⁶ Roelcke showed that University of Heidelberg psychiatry professor Carl Schneider and Rüdin’s Munich associate Julius Deussen “played a leading role in the research on children in the context of the euthanasia program,”²⁷ which included killing children in order to “systematicaly correlate clinical with post-mortem and histopathological data.” Roelcke showed that Rüdin “supported the research efforts of Schneider and Deussen in various ways, among other things with funds from the budget of his own institute in Munich.”²⁸ At least 21 of the 52 children “studied” under the program initiated and supported by Rüdin were killed in order to examine their brains.²⁹ The brains of other murdered “euthanasia” victims were sent to Rüdin’s Munich institute for evaluation and research.³⁰ According to Weber, “Rüdin considered the broadening of the criteria for killing handicapped newborns to be a scientific issue of importance to the war effort.”³¹ In 1944, Rüdin contemplated publishing an article in the Archiv (which he edited) legitimizing “euthanasia” on the basis of “thoroughly investigated children.”³²

Rüdin and his collaborators drafted an internal memorandum on the T4 killing program, which stated:

“Even the euthanasia measures will meet with general understanding and approval, as it becomes established and more generally known that, in each and every case of mental disease, all possible measures were taken either to cure the patients or to improve their state sufficiently to enable them to return to work which is economically worthwhile, either in their original professions or in some other occupation.”³³

And in a 1942 letter to the German Reich Research Council discussing psychiatric genetics and the conditions of war, Rüdin wrote,

“We have no interest in preserving the lives of incurable and ruinous victims of heredity,nor do we have any interest in the propagation of individuals who are carriers of the genetic dispositions necessary for the development of severe hereditary diseases. We do however have an interest in the case of the latter individuals to save what can be saved, at least on a case-by-case basis, by means of timely interventions in pathogenesis and during the course of the disease, in order to at least preserve their utility to society.”³⁴

Rüdin’s verdict for the “incurable and ruinous victims of heredity,” therefore, was death. For the alleged carriers of “genetic dispositions necessary for the development of severe hereditary diseases,” they might be spared this fate, especially those whose “utility to society” would be helpful to the regime and the war effort.

In a 1942 edition of the Archiv, Rüdin wrote,

“The results of our science had earlier attracted much attention (both support and opposition) in national and international circles. Nevertheless, it will always remain the undying, historic achievement of Adolf Hitler and his followers that they dared to take the first trail-blazing and decisive steps toward such brilliant race-hygienic achievement in and for the German people. In so doing, they went beyond the boundaries of purely scientific knowledge. He and his followers were concerned with putting into practice the theories and advances of Nordic race-conceptions . . . the fight against parasitic alien races such as the Jews and Gypsies . . . and preventing the breeding of those with hereditary diseases and those of inferior stock.”³⁵

In the same 1942 article, Rüdin wrote favorably about Nazi racial laws, which led to a “by now progressed elimination of Jewish influence and especially to the prevention of further intrusions of Jewish blood into the German gene pool.”  He saw the war as being caused by “Jewish-plutocratic and Bolshevik directed powers.”³⁶ Chillingly, Rüdin looked forward to eugenic killing and sterilization on a much larger scale following the anticipated German victory, a victory that “will only inspire us…to multiply our racial hygienic efforts.”³⁷

Revisionist Historical Accounts of Rüdin and German Psychiatric Genetics

Major works outside of psychiatric genetics covering many of the crimes of Rüdin and his associates have been available in English since the 1980s,³⁸ although English language documentation of Rüdin’s support for the Nazi regime and the sterilization law dates back to the immediate post-war era and earlier.³⁹

Leading contemporary psychiatric geneticists have written about Rüdin in three main ways, the first two of which should be seen as “revisionist” historical accounts that are the result either of not knowing the facts (or not wanting to make an effort to know the facts), or of consciously distorting and covering up the true history of the field.⁴⁰

Category A

Category A includes leaders of the psychiatric genetics field and their supporters who have written about German psychiatric genetics in the Nazi period and who either fail to mention Rüdin’s name, or cast him in a favorable light.⁴¹ Although some Category A authors discuss Nazi policies and atrocities (at times pointing to the participation of German scientists outside of psychiatric genetics), they do not mention the role of Rüdin and other German psychiatric geneticists in supporting Nazism, racial hygiene, forced sterilization, the killing of mental patients (“euthanasia”), and Hitler’s persecution of Jews, Sinti and Roma (gypsies), gay people, and other targeted groups

As an example, psychiatric genetic researchers Stephen Faraone, Ming Tsuang, and Debby Tsuang, in their 1999 book Genetics of Mental Disorders, wrote of the “Nazi abuses of psychiatric genetics,” and implied only that German psychiatric genetic research had been misused by the Nazis. According to these authors, “Adolph Hitler and his Nazi regime began a systematic program first to sterilize and then to kill ‘genetically defective’ people.” “Contemporary researchers in psychiatric genetics,” they continued, “are especially disturbed to learn that the Nazis used” German psychiatric genetic research conducted “prior to the rise of Hitler” to “justify their eugenics policies regarding the mentally ill.”⁴² In fact, psychiatric genetic research in Germany increased greatly after 1933, with continued funding from the Rockefeller Foundation and other sources,⁴³ and its leaders worked closely with the regime and performed research in support its policies.

Category B

Category B authors acknowledge that Rüdin helped promote eugenic sterilization and/or may have worked with the Nazis, but generally portray his work in a positive light. Category B authors’ accounts deny or fail to mention that Rüdin participated in the “euthanasia” program, and that he supported anti-Semitism and publically endorsed the fight against the “parasitic alien races such as the Jews and Gypsies” while the Holocaust was well underway.⁴⁴

For example, leading schizophrenia genetic researcher Irving Gottesman (whose mentor was the Munich-trained British psychiatric genetic researcher Eliot Slater) and Danish psychiatric geneticist Aksel Bertelsen published a 1996 article in the American Journal of Medical Genetics (Neuropsychiatric Genetics), with the provocative title, “Legacy of German Psychiatric Genetics: Hindsight is Always 20/20.” Gottesman and Bertelsen claimed that when Rüdin heard about the euthanasia program “he declared it to be murder,” and that he joined the Nazi party in 1937 in order to “preserve his life’s work…and to protect his staff, including Jews, for as long as possible.”⁴⁵  They ended this 1996 publication with a quotation from Rüdin’s former psychiatric genetic Munich co-worker Franz J. Kallmann, who wrote a 1947 letter in support of Rüdin for the latter’s denazification hearing, where Rüdin was convicted of being only a Nazi “fellow traveler” and was fined a small amount of money. Kallmann claimed that Rüdin “is no criminal, of course,” and that “if he was guilty at all, his guilt was largely one of omission rather than commission.”

Gottesman and Bertelsen concluded, “We are content to let Kallmann have the last word for now.”⁴⁶ They believed that contemporary re-evaluations of Rüdin’s career based on new evidence amounted to a form of “double jeopardy” (being tried twice for the same offense).⁴⁷ Kallmann left Germany in the mid-1930s, and subsequently played a major role in promoting eugenic ideas in psychiatry, and in establishing the psychiatric genetics field in the United States, until his death in 1965. Between 1944 and 1965, Kallmann published an annual eugenics- and compulsory sterilization-friendly “Review of Psychiatric Progress: Heredity and Eugenics” report in the American Journal of Psychiatry.⁴⁸

Gottesman and Bertelsen were “content” to endorse Kallmann’s conclusion that Rüdin was “no criminal” and that, at most, Rüdin committed crimes of “omission rather than commission.” Gottesman and Bertelsen arrived at this conclusion even though—in the same article—they cited the 1988 English translation of German geneticist Benno Müller-Hill’sMurderous Science. As seen above (endnotes 10, 33, and 35), Müller-Hill documented Rüdin’s support for compulsory eugenic sterilization, Rüdin’s 1935 call to extend the law to cover “valueless individuals” and those with “severe ethical defects,” Rüdin’s participation in the T4 “euthanasia” murder program, and Rüdin’s 1942 article celebrating Hitler’s “fight against parasitic alien races such as the Jews and Gypsies.” Müller-Hill also showed that Kallmann, at a 1935 conference while still working in Germany, had called for extending the compulsory sterilization law to cover many outwardly healthy biological relatives of people labelled with schizophrenia.⁴⁹

Previously, in his 1991 book Schizophrenia Genesis, Gottesman had written about “thoroughly the scientist” Rüdin as the “founder of the Munich school of psychiatric genetics,” and described his work and that of his Munich colleagues in a very positive light.⁵⁰ This did not prevent the American Psychological Association (Division One) from awarding Schizophrenia Genesis its 1991 “William James Book Award.”

Category C

The much less frequent Category C psychiatric genetic writers see Rüdin, in the words of Israeli genetic researchers Bernard Lerer and Ronnen Segman, as “a man who was not only a willing accomplice to the most abhorrent crimes against humanity but an enthusiastic theorist who provided the intellectual basis for many of these crimes.”⁵¹ These researchers concluded,

“There can be only one justification for the name of Ernst Rüdin appearing in a contemporary scientific journal and that is to enable a generation of researchers who may not be fully aware of his tainted legacy, to learn more about it and to appreciate how easily science can be perverted in the service of evil.”⁵²

Other psychiatric genetic researchers, often in letters to the editor of academic journals or in articles written in response to what they perceived as their colleagues’ attempts to whitewash Rüdin’s crimes, have written about Rüdin as an architect and accomplice of unspeakable crimes against humanity.⁵³ American psychiatric genetic researcher Miron Baron suggested that it is “highly likely” that Rüdin used data and information from his own 1916 schizophrenia family study to target family members and their descendants for sterilization during the Nazi period.⁵⁴ Another Category C author went further, writing that “in all probability chronically ill patients from the families that Rüdin used in his epidemiological research were murdered in the T4 euthanasia program.”⁵⁵ And yet, there are revisionist aspects to some Category C publications as well.⁵⁶

Conclusion

Ernst Rüdin was an early champion of eugenic and racial hygienic ideas, ideas that later became part of German National Socialist ideology. It is natural that he welcomed the advent of the National Socialist state in 1933 as an opportunity to put his “thirty-year-old dream” into practice. He also supported the persecution of Jews and other targeted groups. Rüdin and many of his associates worked hand-in-hand with the German National Socialist regime to implement and promote eugenic and “racial hygiene” policies such as compulsory sterilization, and later the outright killing of mental patients and children, and he envisioned the broad extension of this work following the expected German victory in World War II. As the German psychiatric geneticist Peter Propping (Category C) wrote in 2005:

“When the National Socialists came to power in Germany in 1933, the protagonists of the Munich school helped guide psychiatric genetics along the slippery slope from the sterilization of psychiatric patients to their deaths in an organized euthanasia program. Ernst Rüdin was a prominent protagonist of the German racial hygiene movement, his research program as well as his political activities being guided by the idea of a ‘healthy race.'”⁵⁷

Whether Rüdin reluctantly aided and helped implement the “euthanasia” killing program in support of the war effort, or more likely, that he saw it as the crowning achievement of his decades of psychiatric genetic research based on racial hygienic (eugenic) principles, is an issue that may be decided in the future if more documents become available.

The field of psychiatric genetics has, stunningly, failed to produce a complete straight-forward detailed account of its history and origins in Rüdin’s work and German psychiatric genetics. One can only look forward to the long-overdue publication of such a work.

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Footnotes:

1. Joseph, J., & Wetzel, N, (2013), Ernst Rüdin: Hitler’s Racial Hygiene Mastermind, Journal of the History of Biology, 46, 1-30.
2. Siemens, H. W., (1924), Race Hygiene and Heredity, New York: D. Appleton; Siemens, H. W., (1937), Grundzüge der Vererbungslehre, Rassenhygiene und Bevölkerungspolitik [Foundations of Genetics, Racial Hygiene, and Population Policy] (8^th ed.), Munich & Berlin: Lehmanns. For more on Siemens, see Joseph, J., (2004), The Gene Illusion: Genetic Research in Psychiatry and Psychology under the Microscope, New York: Algora, pp. 17-21; see also Teo, T., & Ball, L. C., (2009), Twin Research, Revisionism and Metahistory, History of the Human Sciences, 22, 1-23.
3. Weindling, P., (1989), Health, Race, and German Politics between National Unification and Nazism, 1870-1945, Cambridge: Cambridge University Press, p. 186.
4. Weber, M. M., (1996), Ernst Rüdin, 1874-1952, American Journal of Medical Genetics (Neuropsychiatric Genetics), 67, 323-331, p. 329, p. 325.
5. Joseph, 2004; Joseph, J., (2006), The Missing Gene: Psychiatry, Heredity, and the Fruitless Search for Genes, New York: Algora; Lewis, A., (1934), German Eugenic Legislation, Eugenics Review, 26, 183-191; Luxenburger, H., (1934), “Rassenhygienisch Wichtige Probleme und Ergebnisse der Zwillingspathologie” [Racial Hygienic Important Problems and Results of Twin Pathology], in E. Rüdin (Ed.), Erblehre und Rassenhygiene im Völkischen Staat [Genetics and Racial Hygiene in the Völkish State] (pp. 303-316), Munich: Lehmanns; Rüdin, E., (Ed.), (1934), Erblehre und Rassenhygiene im Völkischen Staat, Munich: Lehmanns; Schulz, B., (1934), Rassenhygienische Eheberatung [Racial Hygienic Marriage Counseling], Volk und Rasse, 9, 138-143; Schulz, B., (1939), Über die Beteutung der Empirischen Erbvorhersageforschung [On the Meaning of Genetic Empirical Prognostic Research], Der Erbarzt, 6, (4), 43-44.
6. Luxenburger, H., (1928), Vorläufiger Bericht über Psychiatrische Serienuntersuchungen an Zwillingen [Provisional Report on a Series of Psychiatric Investigations of Twins], Zeitschrift fur die Gesamte Neurologie und Psychiatrie, 116, 297-347; Luxenburger, H., (1931), Möglichkeiten und Notwendigkeiten für die Psychiatrisch-Eugenische Praxis [Possibilities and Necessities for the Psychiatric-Eugenic Practice], Münchener Medizinische Wochenschrift, 78, 753-758; Luxenburger, H., (1931), Psychiatrische Erbprognose und Eugenik [Psychiatric Genetic Prognosis and Eugenics], Eugenik, 1, 117-124. 
7. Gütt, A., Rüdin, E., & Ruttke, F., (1934), Gesetz zur Verhütung Erbkranken Nachwuchses [Law for the Prevention of Genetically Diseased Offspring], Munich: J. F. Lehmanns.
8. Schneider, F., (2011), Psychiatry under National Socialism: Remembrance and Responsibility, European Archives of Psychiatry and Clinical Neuroscience, 261, Supplement 2, S111-118.
9. Quoted in Weingart, P., (1989), German Eugenics between Science and Politics, Osiris, 5 (second series), 260-282, p. 270.
10. Quoted in Müller-Hill, B., (1998), Murderous Science, Plainview, NY: Cold Spring Harbor Laboratory Press, p. 33. (Original English version published in 1988; original German version published in 1984 as Tödliche Wissenschaft). 
11. Rüdin, E., (1933), Eugenic Sterilization: An Urgent Need, Birth Control Review, 17, 102-104, p. 103.
12. Rüdin, E., (1932), “The Significance of Eugenics and Genetics for Mental Hygiene,” in F. Williams (Ed.), Proceedings of the First International Congress on Mental Hygiene (pp. 471-495), New York: International Committee for Mental Hygiene, p. 483.
13. Weinreich, M., (1946), Hitler’s Professors, New York: Yiddish Scientific Institute—Yivo. 
14. Rosenthal, D., (1971), Genetics of Psychopathology, New York: McGraw-Hill, p. 7. 
15. For example, see Glatt, S. J., Faraone, S. V., & Tsuang, M. T., (2008), “Psychiatric Genetics: A Primer,” in J. Smoller et al., (Eds.), Psychiatric Genetics: Applications in Clinical Practice (pp. 3-26), Washington, DC: American Psychiatric Publishing.
16. Joseph, J., (2015), The Trouble with Twin Studies: A Reassessment of Twin Research in the Social and Behavioral Sciences, New York: Routledge.
17. See Joseph, 2004, 2006, 2015.
18. Turkheimer, E., (2015), Arsonists at the Cathedral, PsycCRITIQUES, 60 (40), 1-4.
19. Torrey, E. F., & Yolken, R. H., (2010), Psychiatric Genocide: Nazi Attempts to Eradicate Schizophrenia, Schizophrenia Bulletin, 36, 26-32. 
20. Ploetz, A., & Rüdin, E., (1938), Zur Entwicklung des Deutschen Reichs seit der Machtübernahme unseres Führers am 30. Januar 1933 [On the Development of the German Reich since our Führer’s Seizure of Power on January 30th, 1933], Archiv für Rassen- und Gesellschaftsbiologie, 32 (2), 185-186. This article was published in German, and was translated in full for the 2013 Joseph and Wetzel article. 
21. Lifton, R. J., (1986), The Nazi Doctors, New York: Basic Books; Proctor, R. N., (1988), Racial Hygiene: Medicine under the Nazis, Cambridge, MA: Harvard University Press.
22. Weiss, S. F., (2010), The Nazi Symbiosis: Human Genetics and Politics in the Third Reich, Chicago: University of Chicago Press, p. 173.
23. Roelcke, V., (2000), “Psychiatrische Wissenschaft im Kontext Nationalsozialistischer Politik und ‘Euthanasie’: Zur Rolle von Ernst Rüdin und der Deutschen Forschungsanstalt/Kaiser-Wilhelm-Institut für Psychiatrie” [Psychiatric Science in the Context of National Socialist Politics and “Euthanasia”: On the Role of Ernst Rüdin and the German Research Institute/Kaiser-Wilhelm Institute for Psychiatry], in D. Kaufmann (Ed.), Die Kaiser-Wilhelm-Gesellschaft im Nationalsozialismus [The Kaiser-Wilhelm Society under National Socialism] (pp. 112-150), Göttingen, Germany: Wallstein; Roelcke, V., (2012), Ernst Rüdin – Renommierter Wissenschaftler, Radikaler Rassenhygieniker [Ernst Rüdin– Distinguished Scientist, Radical Racial Hygienist], Der Nervenarzt, 83, 303-310; Weiss, 2010.. 
24. Weber, 1996, p. 329.
25. Quoted in Weiss, 2010, p. 179.
26. Roelcke, 2000, 2012; Roelcke, V., (2006), “Funding the Scientific Foundations of Race Policies: Ernst Rüdin and the Impact of Career Resources on Psychiatric Genetics, ca 1910-1945,” in W. Eckart (Ed.), Man, Medicine, and the State: The Human Body as an Object of Government Sponsored Medical Research in the 20th Century (pp. 73-87), Stuttgart: Steiner; Roelcke, V., Hohendorf, G., & Rotzoll, M., (1998), Erbpsychologische Forschung im Kontext der “Euthanasie”: Neue Dokumente und Aspekte zu Carl Schneider, Julius Deussen und Ernst Rüdin [Genetic Psychological Research in the Context of “Euthanasia”: New Documents and Aspects on Carl Schneider, Julius Deussen, and Ernst Rüdin], Fortschritte der Neurologie und Psychiatrie, 66, 331-336. 
27. Roelcke, 2006, p. 86.
28. Roelcke, 2006, p. 87.
29. Roelcke, 2000, 2012.
30. Weiss, 2010, p. 183.
31. Weber, M. M., (2000), Psychiatric Research and Science Policy in Germany: The History of the Deutsche Forschungsanstalt für Psychiatrie (German Institute for Psychiatric Research) in Munich from 1917 to 1945, History of Psychiatry, 11, 235-258, p. 255.
32. Quoted in Weiss, 2010, p. 179. 
33. Quoted in Müller-Hill, 1998, p. 46. 
34. Quoted in Ritter, H. J., & Roelcke, V., (2005), Psychiatric Genetics in Munich and Basel between 1925 and 1945: Programs-Practices-Cooperative Arrangements, Osiris (2nd Ser.), 20, 263-288, p. 268.
35. Quoted in Müller-Hill, 1998, p. 67.
36. Rüdin, E., (1942), Zehn Jahre Nationalsozialistischer Staat [Ten Years of the National Socialist State], Archiv für Rassen- und Gesellschaftsbiologie, 36, 321-322, pp. 321-322. 
37. Rüdin, 1942, p. 322.
38. Lifton, 1986; Müller-Hill, 1998; Proctor, 1988; Roelcke, 2006; Weindling, 1989.
39. For example, Bernstein, V. H., (1945, August 21), Created Nazi Science of Murder: Meet “Gentle” Prof. Rudin, Theorist of “Aryanism,” PM Daily, 5; Weinreich, 1946. The authorities in Switzerland, only five days after the German government’s capitulation in May, 1945, decided to revoke Swiss Rüdin’s citizenship for the following reasons:Rüdin belongs definitely to the intellectual leadership circle of the National Socialist regime. He was the expert who prepared the German racial-political legislation which brought immense suffering and ruin for millions of innocent people. Besides his scientific activity he, therefore, played a pronounced political role. Rüdin’s life work contradicts the laws of humanity. (Quoted in Weingart, P., Kroll, J., & Bayertz, K., (1988), Rasse, Blut und Gene: Geschichte der Eugenik und Rassenhygiene in Deutschland [Race, Blood and Genes: History of Eugenics and Racial Hygiene in Germany], Frankfurt am Main: Suhrkamp, p. 569, translated from the original German)
40. Teo & Ball, 2009. Teo and Ball defined revisionism as a “term as referring to a practice that changes historical occurrences by selecting and interpreting events and objects in a new way,” and noted that it sometimes appears in the form of “revisionism by omission.”
41. Examples of Category A publications include: Faraone, S. V., Tsuang, M. T., & Tsuang, D. W., (1999), Genetics of Mental Disorders, New York: Guilford; Flint, J., Greenspan, R. J., & Kendler, K. S., (2010), How Genes Influence Behavior, Oxford, UK: Oxford University Press; Gottesman, I. I., (1991), Schizophrenia Genesis, New York: W. H. Freeman & Company; Gottesman, I. I., & Shields, J., (1982), Schizophrenia: The Epigenetic Puzzle, New York: Cambridge University Press; McGuffin, P., Owen, M. J., O’Donovan, M. C., Thapar, A., & Gottesman, I. I., (1994), Seminars in Psychiatric Genetics, London: Gaskell Press; Rosenthal, D., (1970), Genetic Theory and Abnormal Behavior, New York: McGraw-Hill; Slater, E., (1971), “Autobiographical Sketch,” in J. Shields & I. Gottesman (Eds.), Man, Mind, and Heredity: Selected Papers of Eliot Slater on Psychiatry and Genetics (pp. 1-23), Baltimore: Johns Hopkins Press; Slater, E., & Cowie, V., (1971), The Genetics of Mental Disorders, London: Oxford University Press; Strömgren, E., (1985), “Psychiatric Genetics: Retrospect and Prospect,” in T. Sakai & T. Tsuboi (Eds.), Genetic Aspects of Human Behavior (pp. 3-8), Tokyo: Igaku-Shoin; Torrey, E. F., Bowler, A. E., Taylor, E. H., & Gottesman, I. I., (1994), Schizophrenia and Manic-Depressive Disorder: The Biological Roots of Mental Illness as Revealed by the Landmark Study of Identical Twins, New York: Basic Books. 
42. Faraone et al., 1999, pp. 223-224. 
43. Weiss, 2010.
44. Category B publications include: Cardno, A., & McGuffin, P., (1999), “Psychiatric Genetics,” in H. Freeman (Ed.), A Century of Psychiatry (pp. 343-347), London: Moseby; Farmer, A., & McGuffin, P., (1999), “Ethics and Psychiatric Genetics,” in S. Bloch et al. (Eds.), Psychiatric Ethics (pp. 479-493), Oxford: Oxford University Press; Gottesman, I. I., (2008), Milestones in the History of Behavioral Genetics, Acta Psychologica Sinica, 40, 1042-1050; Gottesman, I. I., & Bertelsen, A., (1996), Legacy of German Psychiatric Genetics: Hindsight is Always 20/20, American Journal of Medical Genetics (Neuropsychiatric Genetics), 67, 317-322; Kendler, K. S., & Prescott, C. A., (2006), Genes, Environment, and Psychopathology, New York: Guilford; Shorter, E., (1997), A History of Psychiatry, New York: Wiley; Zerbin-Rüdin, E., & Kendler, K. S., (1996), Ernst Rüdin (1874-1952) and his Genealogic-Demographic Department in Munich (1917-1986): An Introduction to their Family Studies of Schizophrenia, American Journal of Medical Genetics (Neuropsychiatric Genetics), 67, 332-337.
45. Gottesman & Bertelsen, 1996, p. 320.
46. Gottesman & Bertelsen, 1996, p. 321. 
47. Gottesman & Bertelsen, 1996, p. 317.
48. For example, see Kallmann, F. J., (1952), Review of Psychiatric Progress 1951: Heredity and Eugenics, American Journal of Psychiatry, 108, 500-503.
49. Müller-Hill, 1998, pp. 11, 30-31.
50. Gottesman, I. I., (1991), Schizophrenia Genesis, New York: W. H. Freeman & Company, pp. 13, 68.
51. Lerer, B., & Segman, R. H., (1997), Correspondence Regarding German Psychiatric Genetics and Ernst Rüdin [Letter to the Editor], American Journal of Human Genetics (Neuropsychiatric Genetics), 74, 459-460, p. 459.
52. Lerer & Segman, 1997, p. 460.
53. Category C publications include: Baron, M., (1998), Psychiatric Genetics and Prejudice: Can the Science be Separated from the Scientist?, Molecular Psychiatry, 3, 96-100; Gejman, P. V., (1997), Ernst Rüdin and Nazi Euthanasia: Another Stain on his Career [Letter to the Editor], American Journal of Human Genetics (Neuropsychiatric Genetics), 74, 455-456; Gershon, E. S., (1997), Ernst Rüdin, a Nazi Psychiatrist and Geneticist [Letter to the Editor], American Journal of Human Genetics (Neuropsychiatric Genetics), 74, 457-458; Propping, P., (2005), The Biography of Psychiatric Genetics: From Early Achievements to Historical Burden, from an Anxious Society to Critical Geneticist, American Journal of Medical Genetics Part B (Neuropsychiatric Genetics), 136B (1), 2-7; Schulze, T. G., Fangerau, H., & Propping, P., (2004), From Degeneration to Genetic Susceptibility, from Eugenics to Genetics, from Bezugsziffer to LOD Score: The History of Psychiatric Genetics, International Review of Psychiatry, 16, 260-283.
54. Rüdin, E., (1916), Zur Vererbung und Neuentstehung der Dementia Praecox [On the Heredity and New Development of Dementia Praecox], Berlin: Springer Verlag OHG.
55. Gejman, 1997, p. 456.
56. Joseph & Wetzel, 2013.
57. Propping, 2005, p. 3.