Nosology and vital statistics of dementing conditions of elderly people.

The nosology of dementing conditions of very old people, as described in the International Classification of Diseases, Ninth Revision (ICD-9) and reported in Vital Statistics of the United States, is examined. Methods included a questionnaire of state officials who oversee death certification that asked chiefly about death certificate entries that denote dementing conditions. Current nosology includes several dementing conditions that are commonly indistinguishable without a postmortem examination. Dementing conditions are grouped with other conditions of unrelated pathogenesis. The words "psychosis" and "dementia" are used interchangeably. The majority of state officials said that some death certificate entries denoting dementing conditions are acceptable as causes of death. The current system of nosology of dementing conditions probably results in the under-reporting of these conditions in vital statistics. The tenth revision of the International Classification of Diseases (ICD-10) classifies dementing conditions similarly to the ninth revision. An alternative system of nosology, based on dementia as a common characteristic, is suggested.