Calibrating diagnostic practices: The role of psychiatric diagnoses for mental health professionals’ everyday practice

Psychiatric diagnoses play an increasingly important role in contemporary societies, with more people meeting the criteria for receiving one, and a growing number of actors holding an interest in them. However, there is little empirical research on how this development influences clinical practice. The aim of this study is to explore the role of diagnosis and diagnostic manuals in everyday clinical psychiatric practice and to examine how these practices are influenced by those of other diagnostic actors. Drawing on a multimethod qualitative inquiry based on four months participant observations and interviews with 13 mental health professionals from a psychiatric inpatient and an outpatient clinic in Denmark conducted between 2023 and 2024, we find that mental health practitioners habitually engage in what we term expansive practices. That is, they employ a broad range of alternative classifications to grasp the complexity of patients' problems and calibrate their practice accordingly - a task to which manuals and clinical guidelines are often perceived as inadequate. Unlike previous theoretical suggestions, we find that mental health practitioners do not uncritically adopt standardized checklist approaches to diagnosis. Rather, they relate to other diagnostic actors' interests and use of diagnosis, which subsequently influence their clinical practice.