Diagnostic staging and stratification in psychiatry and oncology: clarifying their conceptual, epistemological and ethical implications.

Staging and stratification are two diagnostic approaches that have introduced a more dynamic outlook on the development of diseases, thus participating in blurring the line between the normal and the pathological. First, diagnostic staging, aiming to capture how diseases evolve in time and/or space through identifiable and gradually more severe stages, may be said to lean on an underlying assumption of "temporal determinism". Stratification, on the other hand, allows for the identification of various prognostic or predictive subgroups based on specific markers, relying on a more "mechanistic" or "statistical" form of determinism. There are two medical fields in which these developments have played a significant role and have given rise to sometimes profound nosological transformations: oncology and psychiatry. Drawing on examples from these two fields, this paper aims to provide much needed conceptual clarifications on both staging and stratification in order to outline how several epistemological and ethical issues may, in turn, arise. We argue that diagnostic staging ought to be detached from the assumption of temporal determinism, though it should still play an essential role in adapting interventions to stage. In doing so, it would help counterbalance stratification's own epistemological and ethical shortcomings. In this sense, the reflections and propositions developed in psychiatry can offer invaluable insights regarding how adopting a more transdiagnostic and cross-cutting perspective on temporality and disease dynamics may help combine both staging and stratification in clinical practice.

[Oncology and psychiatry: Towards mutual connections/relationships]. / Oncologie et psychiatrie - Pour une relation réciproque féconde.

Oncology has been proposed as a model of scientificity, in order to promote scientific approaches to psychiatry. In this article, another type of relation between oncology and psychiatry is explored, which promotes the idea of a mutually enriching dialogue and underlines the contributions of psychiatry to oncology. The ways in which both fields address epistemological and ethical issues in their respective approaches to disease is also examined. We argue that these two disciplines can learn from one another in the common context of chronic conditions, thanks to the potential of big data collection and their biostatistics treatment for the identification of markers - sources of individualization -, as well as thanks to the renewed attention given to the temporal and processual dimension of these diseases, in particular within the framework of "staging" models.

Title: Oncologie et psychiatrie - Pour une relation réciproque féconde. Abstract: L'oncologie est souvent considérée par les défenseurs d'une psychiatrie scientifique comme un modèle médical à imiter. Psychiatres, oncologues et philosophes, nous proposons dans cet article une autre manière d'envisager les relations entre oncologie et psychiatrie, en promouvant l'intérêt d'un dialogue entre ces disciplines, convaincus de leur potentiel enrichissement réciproque et, en particulier, des apports possibles de la psychiatrie à l'oncologie. Nous proposons d'étudier chacune des manières de faire face aux difficultés épistémologiques et éthiques rencontrées dans l'approche des maladies. Nous pensons que psychiatrie et oncologie peuvent apprendre l'une de l'autre, dans le contexte commun de maladies chroniques qu'il s'agit de gérer plutôt que de guérir, grâce au potentiel qu'offrent le recueil de données massives et leur traitement biostatistique pour l'identification de marqueurs permettant d'individualiser les traitements, ainsi que grâce à l'attention renouvelée accordée à la dimension temporelle et processuelle de ces maladies, notamment dans le cadre de modèles de « stadification ¼ (ou staging).