What are the functions of psychiatric classifications?

Faced with clinical, methodological, conceptual and modeling challenges, psychiatric nosology turned forty years ago towards a descriptive approach, with the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III). More recently, the discipline has sought answers in precision medicine and biomarkers, e.g., with the Research Domain Criteria project of the National Institute for Mental Health, towards statistical and dimensional approaches, e.g., the Hierarchical Taxonomy of Psychopathology, or towards dynamic (e.g., staging models) and computational approaches (e.g., symptom network in psychopathology). However, despite these attempts to guardedly move away from a descriptive perspective, the functions of classifications have remained the same in psychiatry over time. These functions could be seen as the guarantee of a stable ground for psychiatry, and it seems necessary that they be made explicit from methodological and deontological points of view.