HIGH PREVALENCE OF DEMENTIA AMONG PEOPLE WITH LEARNING-DISABILITIES NOT ATTRIBUTABLE TO DOWNS-SYNDROME

Background. For many years, it has been known that dementia can occur in people with learning disabilities, but there have been few research studies. Studies that do quote rates for dementia show these to be hi gh, but this important fact has received remarkably little attention. Method. Comprehensive psychiatric and medical assessments were underta ken on the whole population (ascertained as far as is possible) of peo ple with learning disabilities aged 65 years and over living in Leices tershire, UK (N = 134), in order to ascertain rates of DCR defined dem entia, and associated factors. Results. Dementia was diagnosed in 21.6 %, against an expected prevalence of 57 %, for a group with this age structure. The rate of dementia increased in successive age cohorts: 1 5.6 % aged 65-74 years; 23.5 % aged 65-84 years; and 70.0 % aged 85-94 years. People with dementia tended to be older, female, with more poo rly controlled epilepsy, a larger number of additional physical disord ers, less likely to be smokers and had lower adaptive behaviour scores than did the elderly people without dementia. They were more likely t o live in health service accommodation. Conclusions. Dementia occurs a t a much higher rate among elderly people with learning disabilities t han it does among the general population; this is independent of the a ssociation between dementia and Down's syndrome. Whether this relates aetiologically to genetics, lack of brain 'reserve' or history of brai n damage is yet to be determined.