Thomas Kuhn's model of the structure of scientific procedure is outlined and applied to salient aspects of recent psychopharmacological research into the bioneural substrates of the affective disorders. It is argued that the amine hypotheses of these disorders are irrefutable in practice although not in principle and that their survival despite a lack of convincing supporting evidence and dis-proof of their initial premises suggests that they serve a paradigmatic function and that the core of this paradigm is psychological in nature rather than neurobiological. An attempt is made to show how an awareness of such functions may help explain otherwise puzzling features of the literature on the psychopharmacology of the affective disorders. Such an awareness may also help to indicate the steps necessary to replace the amine hypotheses or the likely future prospects for these hypotheses.