The notion of “social treatment” allows considering that autism presents a certain form of reality before being the object of different kinds of practices and knowledge. The notion of “social treatment” is preferred to that of “social construction” to avoid the idea that autism acquires a form of reality only through its social construction. The title's choice traduces a will to take distance from constructivism. All the categories have a social origin insofar as they are based on a socially produced frame, but categorizations are always put to the test of the world's materiality through our experiences. This thesis presupposes that autism's reality is the object of a continual and collective process of reassertion and revision. Why designating autism as a medical diagnosis? It is autism as the object of a human knowledge, which makes of it a socially produced reality, that becomes analyzable by the sociologist. To characterize autism as a medical diagnosis indicates that the purpose of this thesis is to grasp the continual and practical accomplishment of autism's categorization. This thesis relies methodologically on an ethnographical approach, and theoretically on the pragmatic sociology, to propose a sociological study of medical diagnosis from the case of autism. The first part deals with diagnosis as a category and aims at showing how this category is caught in different socio-political stakes. These socio-political stakes are highlighted through distinguishing four dimensions that shape the diagnosis of autism: its institution, its institutionalization, its politicization and its controversy. Theses dimensions permit to understand the stakes that shape diagnosis in the medical world and beyond. This part shows how diagnosis as a category is constructed at the crossroads of several logics that circulate in different worlds, through power relations between different kinds of actors, in a configuration that is likely to evolve over time. The second part deals with diagnosis as a process of qualification. From the observation of an evaluation center specialized in autism diagnosis, this part proposes a sociological analysis of the medical qualification. In this perspective, diagnosis is regarded as an activity, a work that can be traced step by step, and the sociologist is interested in the practices through which diagnosis is locally produced. After situating my work in a pragmatic approach of medical expertise, and proposing an analysis grid of the operation of qualification, this part studies the linkage between the different steps of the diagnostic process. This part allows conceiving diagnosis as a process that is determined by the configuration and the supports of the qualification, and situated in a context characterized by a plurality of diagnostic practices. The third part deals with the practical implications of diagnosis. This part grasps the implications of diagnosis outside of the medical world, in other contexts of action, in the administrative and school worlds. It also highlights the implications of diagnosis on family, through the analysis of the domestic production of care. It proposes to analyze the implications of diagnosis on the ways the child's subjectivity is treated. Eventually, this part underlines a phenomenon of paths dualization, in terms of practical arrangements of care and diagnosis quest, which may be analyzed through different reading grids that do not support the same criticism of social inequalities.
