‘titrebSummary’/titrebParler of a structure in Psychiatry might seem random, unnecessary or futile, or even ‘archaic’. More argued and taken in a complex theorisation Jacques Derrida was able to say that ‘deconstruction’ was born at his home when ‘everything was spoken’, ‘at a time when structuring was dominant’... We establish here, with the help of references to Jean Piaget, and in one of his last books in Jean-Claude Milner, the origins and developments of this term of structure. This is obviously in different disciplines. This makes it necessary to distinguish at least three points: what ‘on’ has referred to as ‘structural’ current or movement, in a more or less imprecise manner, categorical and then critically; research and a method according to a certain scientific formalism; and for the field of Psychiatry, what was already used in the context of nosography and its nosologies.The scientific aspect seems to be contained in the origin of the so-called structural method.