How American Eugenics Fueled Nazi Euthanasia: Psychiatry's Forgotten Complicity in the Holocaust

Did American eugenics really fuel the murderous euthanasia programs of the Nazis? Yes, according to Susanne Paola Antonetta, author of The Devil’s Castle, a history of Nazi eugenics and euthanasia. According to Antonetta, pioneering American eugenicists not only influenced Nazi thinking—Hitler himself corresponded with them and praised U.S. sterilization laws in Mein Kampf—but the New York City-based Carnegie Institute proposed gas chambers in 1918 as one solution for dealing with what eugenicists called the ‘hereditarily tainted’ population. While Germany’s response was uniquely brutal, Antonetta argues that American psychiatric thinking provided the conceptual framework for deciding whose lives had value and whose didn’t. Moreover, the notorious Nazi Aktion T4 euthanasia program killed 300,000 people with neuropsychiatric disorders, yet it was never properly prosecuted by the Americans at Nuremberg and remains largely unknown today.

1. American Eugenics Provided the Blueprint The U.S. passed sterilization laws in 1907—decades before Germany’s 1933 laws. Hitler praised American eugenics in Mein Kampf, American eugenicists taught in Germany, and the Carnegie Institute proposed gas chambers in 1918 for the “hereditarily tainted.” The conceptual architecture was Made in America.

2. Action T4 Killed 300,000 and Was Never Prosecuted The Nazi euthanasia program murdered roughly 300,000 people with neuropsychiatric disorders in gas chambers built into asylums. Because Nuremberg only tried international crimes—not crimes against a nation’s own citizens—this program escaped proper legal reckoning and remains largely unknown.

3. Doctors Could Say No—But Didn’t Some asylum doctors, like Carl Kleist, simply refused to participate in T4 and faced no punishment. This makes the complicity of other doctors—many of them idealistic, not monsters—more damning. The system allowed for refusal; most chose collaboration.

4. Psychiatry Still Assigns Value to Lives Antonetta argues that psychiatry’s troubled legacy persists: rigid diagnostic categories inherited from German psychiatrist Emil Kraepelin, neurotransmitter theories that haven’t improved outcomes, and a system that still decides whose consciousness has value. The DSM itself was created by self-described “neo-Kraepelinians.”

5. Neurodiversity Is the New Civil Rights Frontier From autism to schizophrenia, our public discourse about neurodiversity remains “relentlessly negative.” As CRISPR and gene editing become reality, Antonetta warns we’re facing the same eugenic questions—but now with the tools to act on them. We need more honest and nuanced conversations about different forms of consciousness before we start editing them out.

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