ABSTRACT
The early studies of epidemiology of dementia in North America, now primarily of historical interest, have been reviewed elsewhere (Eastwood et al, 1991). The early mental hospital studies dealt mainly with such diagnostic categories as senile psychoses and cerebral arteriosclerosis. Studies in Massachusetts and New York state in the first part of the 20th century suggested that cerebral arteriosclerosis was increasing (Elkind and Taylor, 1936; Malzberg, 1935; Landis and Page, 1938). These authors recognized that there were nosocomial effects and that the differential diagnosis of these disorders was often difficult and that the conditions frequently coexisted.
