Among the more frequently quoted epidemiological facts in current public health discussions are: (a) the elderly today represent about 10% of the population of the industrialized world; (b) the third world nations are moving in the same direction; (c) the trend toward a growing proportion of the aged in the world population will continue over the next few decades; (d) people over 80 now represent the fa. stest growing sector in North America; (e) in the elderly, general morbidity - and particularly morbidity of the central nervous syste- is many times that in the younger popUlation; (f) 5% of those over 65 years of age and 20% of those over 80 suffer from some degree of dementia. A global tidal wave of patients suf fering from Alzheimer's disease (or senile dementia) is threat ening to engulf us by the year 2000. This disease, which is, at our present state of knowledge, ir reversible, and other age-related dementias are perhaps the most sinister forms of any disability. They deprive their vic tims not only of their physical capacities but also of their autonomy and their ability to think and to make decisions for themselves. The future cost of psychogeriatric diseases in terms of suffering for individuals, stress for families, demand for manpower, and budgetary requirements for governments could become astronomical.