Background: Despite being often taken as the benchmark of quality for diagnostic and classificatory tools, 'validity' is admitted as a poorly worked out notion in psychiatric nosology. Objective: Here we aim at presenting a view that we believe to do better justice to the significance of the notion of validity, as well as at explaining away some misconceptions and inappropriate expectations regarding this attribute in the aforementioned context. Method: The notion of validity is addressed taking into account its role, the (...) framework according to which it should be assessed and the specific contents to which it refers within psychiatric nosology. Results and Conclusions: The notion of validity has an epistemological thrust and its foremost role is distinguishing correct reasoning and truth from what is irrational or false. From it follows not only that 'validity' always refers to elements of knowledge and rationality such as arguments, inferences and propositions, but also that the appropriate frameworks to assess 'validity' are logics and scientific methodology. When the validity of a psychiatric diagnostic category is at stake, the contents to which it refers are those relevantly related to the notion of 'diagnostic concept'. The consequences of our reading on the notion of 'validity' are discussed vis-à-vis the challenges faced by psychiatric nosology in order to have its diagnostic categories validated. (shrink)

Dear Editor, in a previous paper we have tried to delve into what validity means in the context of psychiatric nosology, arguing for a pragmatic view of it. Here we want to briefly reassert the basic points of our analysis, make a few clarifications and address some issues raised by commentators.

What we call today negative symptoms are thought to descend from the very deficits that the earliest scholars of schizophrenia (such as Kraepelin and Bleuler) considered to be the key, fundamental symptoms of the disorder. In the latter half of the 20th century, delusions and hallucinations received greater prominence, which eventually changed both the concept of schizophrenia and its diagnostic criteria by placing positive symptoms at the forefront. The first decade of the 21st century witnessed a resurgence of interest in (...) negative symptoms of schizophrenia. Persistent and clinically significant negative symptoms were declared an unmet therapeutic need in a large proportion of cases by several schizophrenia experts, who, with the support of the NIMH, held a consensus development conference in 2005 to discuss negative symptoms and how to proceed in this area. The Consensus Statement read that improved recognition and awareness of negative symptoms are the fi rst step to improving function in patients with negative symptoms of schizophrenia. According to the principles of Values-Based Practice that also means improving recognition and awareness of the diverse values involved in the conceptualization and practical assessment of negative symptoms. By analyzing selected conceptual papers on negative symptoms, instruments developed for the assessment of this area of psychopathology, and clinical vignettes, we intend to point out some values-related issues in the diagnosis of negative symptoms as well as to make the case that these symptoms may be a particularly complex aspect of schizophrenia, vis-à- vis understanding the role played by values. (shrink)