Abstract
The recognition of a well-established psychosis due to arteriosclerotic or senile brain changes rarely presents any difficulty. However, increasing numbers of elderly people are seen with affective, paranoid, or neurotic manifestations, and it is sometimes very difficult to decide whether their symptoms present prodromata of an organic psychosis, or whether in the absence of degenerative brain disease they are occasioned by a variety of endogenous and environmental causes leading to a “functional” psychiatric illness.