Philippe Le Moigne holds a PhD in sociology. He is a researcher at the French Institute of Health and Medical Research (INSERM), and teaches at the University of Paris René Descartes.His research first focused on the prescription and consumption of psychotropic drugs in the general population. He then became interested in the history, use and epistemology of measuring instruments designed by psychiatry, particularly in the field of depression. This question led him later to address more broadly the problem of the applicability of experimental methods to the knowledge and treatment of mental disorders.In these different areas, Philippe Le Moigne's analyzes focus on the effects that the personalization of social life has had on psychiatric practice and research. He showed how this trend has given legitimacy to individual ill-being and worked in this direction to spread psychotropic drugs, well beyond the treatment of mental disorders. In the same way, Philippe Le Moigne sought to explain why the use of measuring instruments ended up dominating psychiatric knowledge, showing how, in this context of personalization, clinical practice seemed to be able to give rise only to subjective judgments