Roth and Morrisey (1952), in isolating senile dementia (senile psychosis) as a distinct nosological entity, used as their definition “an illness of insidious onset pursuing a uniformly progressive course with steadily augmenting mental decay”. In 1955 Roth defined senile psychosis as “a condition with a history of gradual and continuously progressive failure in the common activities of everyday life and a clinical picture dominated by failure of memory and intellect and disorganization of a personality, where these were not attributable to specific causes such as infection, neoplasm, chronic intoxication or cerebral vascular disease known to have produced cerebral infarction”. Kay (1962) defines dementia as a “gross deterioration of intellectual capacity and of memory, together with severe and persistent disorientation for time and place”. He diagnosed senile dementia “when there was no evidence of focal brain disease”. Roth et al. (1966) describe senile dementia as “the extreme form of intellectual decay of old age”.