The history of spiritism and psychiatry share several common elements and intersections. However, historians have inadequately explored this subject.Particularly in Brazil, there has been an intense, but little studied conflict between psychiatrists and spiritists in regards to "Spiritist Madness" during the first half of the twentieth century.This present study investigates the construction of the representation of mediumship as madness: the "Spiritist Madness". In other words, how spiritist mediumistic experiences became classified by psychiatrists as a cause and/or manifestation of mental disorders. This study focuses on the place and the time where this conflict was more severe, in the southeast of Brazil, between 1900 to 1950.In Brazil, during the first half of the twentieth century, both, psychiatry and spiritism were seeking legitimation, through cultural, scientific, and institutional means within Brazilian society. These two social actors were related to urban, intellectualized classes, proposing different views and therapeutic approaches to the mind and madness. Both disputed the same space within scientific, cultural, social, and institutional fields, attempting to each establish their own legitimation. This conflict was expressed through constant quarrels between psychiatrists and spiritists. Physicians published academic theses, papers, and books about "spiritist madness" and the need to oppose it through governmental control of spiritist groups, forbidding spiritist publications, fighting against charlatanry allegedly practiced by mediums, and hospitalization of mediums, regarded as insane. On the other hand, spiritists also published books, wrote papers in spiritist periodicals, produced a thesis in medicine (that was reproved), and built spiritist psychiatric hospitals. Besides defending against mediumship as a sort of V madness, spiritists defended spiritism and criticized psychiatry for its poor clinical effectiveness and for not taking into account possible spiritual causes of madness. This struggle was reported by the lay media, and a large number of articles about this subject were printed in large circulation newspapers.The resolution of this conflict is related to the achievement of social integration and legitimation by both spiritism and psychiatry, although in different fields.Psychiatry found its place basically within medical and academic environments; on the other hand spiritism received its legitimation mainly within the religious field. However, representations of mental disorders' in Brazilian society have suffered influences from both groups. A large proportion of Brazilians seek spiritual treatments as a complement to psychiatric therapies. Psychiatric and spiritist representations of mental disorders are often understood more as complementary rather than opposed. This symbolic dispute between representations about the mind, madness and mediumship has had its role in the constitution of psychiatry and spiritism as we understand presently in Brazil. This conflict provided psychiat...