This thesis aims to reaffirm the necessity of the debate about the status of truth in the context of knowledge production about psychic suffering. It states, first and foremost, that 'truth' is employed in two different outlines: on one hand, it is employed to legitimize produced knowledge, thus establishing normative patterns; while on the other hand it is presented as a disruptive element, working as a critical instance to established knowledge. Considering truth in such terms locates knowledge in terms both of its necessary as its variable character, and the term 'truth' itself stand dependent on epistemological, ontological, ethical and political elements. This standpoint articulates with Ian Hacking's historicized understanding of science, which enables the consideration of contingent bases to scientific practice but still producing knowledge that must be considered as necessary. In this sense, it is possible to establish a field in which normative understandings about scientific praxis might be criticized without resulting in any kind of refusal or disqualification of the produced knowledge. In addition, his proposition of a "historical ontology" and of a "dynamic nominalism" presents an important contribution to understand the workings of knowledge production in the context of psychical suffering, by introducing into the debate the consideration of the ontological effects of produced knowledge. Taking these issues into account the thesis moves on to the matter of the way in which the concept of truth is construed within Lacanian psychoanalysis, focusing on three main elements: 1. truth's autonomy toward the subject (truth speaks), 2. the opposing and temporary character of a positivized truth facing established knowledge (truth as critique), and 3. the negative dimension of truth, which relates to the inexhaustibility of this dialectical process of negations (truth as radical difference). It is argued that it is possible to sustain a particular reasoning style (in Hacking's terms) for psychoanalysis, based on a radical conception of negativity. Also, both rationalities (Lacan's and Hacking's) work with a historicized understanding of knowledge that does not have any external (nor internal) criteria to warrant its truth. However, psychoanalysis takes negativity beyond Hacking's philosophy of science, offering a wider range of possibilities when thinking about causality for psychic suffering. Both ways (albeit with different intensities) lead to a consideration of the necessary ethical and political implication in knowledge production and deploymentonce there is no epistemological warranty to knowledge, its production value is tied to social agreements and ethical positionings. There is, therefore, the necessity of considering power relations.