ABSTRACT
Sleep medicine is a young field and its nosology is far from fixed. The idea that the study of sleep physiology might evolve into a branch of medicine devoted to disorders of sleep arose during the 1960s. The first attempt to classify sleep disorders had its origin in a workshop at the 1972 annual meeting of the Association for the Psychophysiological Study of Sleep (APSS), resulting in the establishment of a Nosology Committee in 1976. Since then, three major classifications of sleep disorders have been published, the most recent in 2005. This ongoing process reflects a dynamic field of medicine, responsive to current practice and research.
