This PhD thesis analyses the institutionalization of organizational practices with the psychiatric diagnostic as a field of study. Fundamentally attached to the organization as an empirical object, we will try to answer a research question deeply rooted in it: what are the organizational phenomenons involved in the daily institutionalization of practices? Our work will tackle three mains issues: theoretical, epistemological and empirical.In a first time, we will clarify the concept of organizational practice. If the practice turn is now well engaged in Organization Studies, scholars are still far from a theory that would have given a clear definition of its central concept. We will provide a review of the literature on practice that considers the process of institutionalization as its birth. This will lead to a grid analyzing the multiple institutionalized ways of doing that are practices.In a second time, we will address an epistemological issue. Practices, classical empirical objects in sociology and anthropology, are central elements of the social life that cannot be easily captured through classical theoretical categories. We will have to go further in the concept in order to get out of the epistemological dead-end that the elaboration of a theory of practice is. In fact, it is a theory of practical logic that will be our real project, and precisely, the historical origins of this practice and its daily transmission.In a third time, we will face our field study loaded with these requirements. Behind classical methodological difficulties, it is the restitution of a fine-grained practical understanding produced by several months of immersion that will be challenging. In order to respect the field’s abundance and to not reduce it to a series of observations seen through a theoretical lens, we choose to present a scenarized synthesis that will condense our six-months study into a four-weeks story of a psychiatric department in a teaching hospital. This stylistic solution will allow us to account for a field that always overwhelms our perspective: the institutionalization of organizational practices.
