The *validity of psychiatric nosology

This dissertation has three tasks: to analyze the philosophy behind our current psychiatric nosology, to analyze and refute the myriad criticisms of that nosology, and to provide a more sophisticated understanding of what it is to have nosologic validity in general. Whereas most disease classifications do not generate much controversy, the current psychiatric nosology, the Diagnostic and Statistical Manual of Mental Disorders (DSM) constitutes a nearly universal focus for criticism, usually on philosophical grounds. However, neither critics not proponents of the DSM provide clear and defensible arguments for their positions. In order to remedy this situation, and to clear the way for more productive discussions about the validity of psychiatric nosology, I analyze both the DSM and the criticisms most commonly made of it. I compare psychiatric nosology to other classifications in biology and medicine; and I draw on insights from those sciences to determine which philosophical concerns about the DSM need to be taken seriously. I dispel several sources of misunderstanding about nosologic validity; and I recast questions about the nosologic validity of the DSM in terms of process rather than product. I conclude that in light of the tripartite view of nosologic validity used in psychology, the DSM is valid. However, I challenge the authors of the next edition of the DSM to clarify its methodological and philosophical assumptions so that further confusion about the validity of the DSM might be avoided