Disease entities and the borderline between health and disease: Where is the place of gradations?

The chapter discusses the demarcation of health and disease by considering ‘disease entity’ as the most fundamental notion in the theory of medicine. First, it provides an analysis of the conceptual structure of the medical theory of disease and nosology. It demonstrates that the most central theoretical tool of fully developed medical disciplines is the concept of disease entity. Second, the chapter demonstrates that individual cases of disease entities differ typically according to their stages and degrees of severity. Third, the chapter argues that psychiatry is not yet a fully developed medical discipline and is lacking a mature nosological structure. The conclusion is that, for diagnostic and practical purposes, psychiatry is not in need of gradations between health and disease in general, but rather of empirically sound and validated gradations that address the kind, stage, and severity of its nosological entities, including its provisional surrogates for proper disease entities.