The scope of this article is to show the importance of a highly naturalized model of human actions that, taking as its pivotal point a hereditary explanation, was widely used by Portuguese psychiatry at the close of the 19th century, in continuity with what was happening in the European context. 'Degeneration' was instituted as a species of chart, based on which experiences were classified and described with occasionally threatening contours for a certain conception of the social and political order. Various phenomena, nosologically described in differentiated forms, came to be integrated into the language of degeneration. Its expansive and supposed metatheoretical character became involved in its death throes, coming to be progressively replaced by another model, psychoanalysis.
psychiatry; degeneration; psychoanalysis; 19th century; Portugal