ABSTRACT
In the nineteenth century, books were written about a number of behavioral disorders, among them hebephrenia, catatonia, and paranoid dementia. These disorders were often elegantly described, and viewed as discrete diagnostic categories. Kraepelin, of course, changed this with his conception of dementia praecox. The previously mentioned disorders were now viewed as subtypes of a single entity, defined more on the basis of course than on symptoms. That is, members of a single class, dementia praecox, were thought to share a common course (early onset and progressive deterioration) even though their specific symptoms might vary widely.
