Hermilio Valdizán published several papers on what was called psychiatric folklore, understood as the ways of understanding and treating mental illnesses by indigenous people, both from the colonial and pre-Hispanic past and from the author's present. In this article, we analyze Valdizán's texts on the psychiatric and psychological characteristics of indigenous Peruvians. From the perspective of this psychiatrist, contemporary indigenous people were archaeological remains of the ancient Inca empire, ruins in the process of degeneration. In a context marked by indigenism, in which it was sought to integrate the Indians, psychiatry played a conservative and racist role that reproduced evolutionary models of the nineteenth century.