The article describes the emergence of research programmes, institutions and activities of the early protagonists in the field of psychiatric genetics: Ernst Rüdin in Munich, Eliot Slater in London, Franz Kallmann in New York and Erik Essen-Möller in Lund. During the 1930s and well into the Nazi period, the last three had been research fellows at the German Research Institute for Psychiatry in Munich. It is documented that there was a continuous mutual exchange of scientific ideas and practices between these actors, and that in all four contexts there were intrinsic relations between eugenic motivations and genetic research, but with specific national adaptations.
Keywords: Eliot Slater; Erik Essen-Möller; Ernst Rüdin; Franz Kallmann; population genetics; psychiatric genetics; racial hygiene.