Molecular complexity: Why has psychiatry not been revolutionized by genomics (yet)?

International audienceThis chapter looks into the results of Genome-Wide Associations Studies, one of the leading trends in molecular psychiatry. The main reason for their lim- ited achievements to-date is precisely what they have been designed to handle: complexity. Yet this much used term needs further clarification in the context of Genome-Wide Association Studies. A distinction should be made between 1) unreliable phenotypes, a problem that may eventually solve itself with a molecular approach, 2) complex inheritance processes, and 3) complex mecha- nisms, in the forms of genomic, etiological and pathophysiological complexity. This situation is of interest to the study of several traditional questions in the philosophy of medicine