ABSTRACT
INTRODUCTION Classification in medicine serves several purposes. In the clinical arena, disease classification is used to identify individuals with a consistent set of symptoms and signs. This permits conditions of a similar type or etiology to be recognized and discriminated from other conditions, and helps to guide therapeutic interventions. In serving these functions, classification provides a sort of “shorthand” for communication among professionals. Additionally, classification is important for administrative functions such as medical record-keeping and billing. Within the research arena, classification provides consistency in the identification of “cases” for scientific investigation into epidemiology, course, etiology, pathophysiology, and treatment. Ideally, the conceptualization and classification of disorders informs research into their etiology and treatment, and such research leads back to refinements of conceptualization and classification. Generalizations regarding etiology and treatment efficacy depend on reliable and valid diagnoses. In this chapter, we will briefly review some general aspects of disease classification, and present an overview regarding classification of insomnia, highlighting findings from empirical research studies.
