After World War II, Abderhalden returned to Switzerland in 1945 and lectured physiological chemistry at the University of Zurich as the replacement of Bonifaz Flaschenträger, who had to leave due to his membership in the NSDAP.
[11] In late 1912 Abderhalden's "defensive ferments reaction test" was applied to the differential diagnosis of dementia praecox from other mental diseases and from normals by Stuttgart psychiatrist August Fauser (1856–1938), and his miraculous claims of success were soon replicated by researchers in Germany and particularly in the United States.
However, despite the worldwide publicity this "blood test for madness" generated, within a few years the "Abderhalden–Fauser reaction" was discredited and only a handful of American psychiatric researchers continued to believe in it.
Otto Westphal described Abderhalden's work in conversation with Ute Deichmann as follows:[15]I had no doubt in the beginning myself, in fact I wrote a review on the Abwehrfermente in 1939.
The whole Abwehrfermente story was a fraud from beginning to end.Abderhalden's work was strongly ideologically slanted: his theory was put to use for human experiments by Otmar von Verschuer and Josef Mengele to develop a blood test for separating "Aryan" from "non-Aryan" individuals.
While Abderhalden himself did not take part in this work, evidence suggests that he was instrumental in ideologically streamlining the German Academy of Natural Scientists Leopoldina by having the Jewish members purged and replaced by Nazi sycophants.
In an interim report of the KWI-A at the German Research Foundation, which funded the project, Verschuer explained that his assistant was posted as a camp doctor in Auschwitz, Mengele, who was entered as an employee in this branch.
"With the permission of the Reichsführer-SS be conducted anthropological studies of the various racial groups in this concentration camp and sent the blood samples to my laboratory for processing."
Also, the biochemist Günther Hillmann was included in the project, and was established as a specialist for protein research by the Kaiser Wilhelm Institute for Biochemistry under Adolf Butenandt.
Verschuer spoke in this context of 200 studied blood samples from family members of different "races" which substrates are made of.
The most comprehensive analysis of the issue as to whether Abderhalden was simply grossly mistaken or perpetuated deliberate fraud can be found in Kaasch.