Abstract. The vast majority of studies on the history of psychiatry is devoted to a period that begins at the ” classical age ” and ends in the late nineteenth century. Our historical analysis , discusses the production of mental medicine in the heart of the twentieth century. By the end of the Second World War, the properties of multiple substances assumed to act on the mind were intensely explored , analyzed, codified and manipulated. We will see how these substances initially aimed to primarily exploration of a supposed truth of the subject by the induction speech. Then, we will consider the genealogy and peculiarities experiences with chlorpromazine , called neuroleptic. In recent years, these experiences have forged new practices and new discourse on the power of drugs, on mental illness and on the subject, which continue until this day under two forms: one disciplinary; psychopharmacology and the other transgressive, known as modern addiction. Today psychoactive substances and their effects are in crisis. Their promises of efficiency and assumptions not remain valid . A neuroscience of a neo-localizationism marked by medical imaging and brain circuits seems to take over. This article attempts to explain how and in what way these transformations, far beyond of modern psychiatry, have profoundly affected the assumptions, practices and representations, in terms of both mental illness than the construction of the contemporary subject.