The history of psychiatry is characterised by the confrontation of theoretical models, or dualism.The contrast between these trends has always added to the richness of this discipline, from Philippe Pinel to Henri Ey, and from Bénédict-Augustin Morel to Valentin Magnan.Today, we are faced with an epistemological malaise which is the result of the domination of neurosciences. In order to protect against the temptation to allow the domination of one of the theoretical models, a return to dualism is recommended.