Mortality and dementia among ageing defectives.
From a detailed case-register of the ascertained mentally handicapped in a defined population, 382 individuals were identified with an IQ of 50 or under, and of age 57 or over at follow-up 12 years later. In the 277 patients initially in hospital, case records and clinical examination of the survivors showed a life expectancy and a prevalence of dementia similar to that found in the general population. The 105 individuals originally resident in the community had made little demand upon hospital services over the period. The survival to old age of the mentally handicapped poses a quantitative problem for mental deficiency hospitals, but no evidence was found to suggest that provision of high-dependency care above the level required for the general population is needed.