Hebephrenia Hecker-Kahlbaum and E. Kraepelin's teaching on dementia praecox

In the 90s of the last century, to the arena of clinical psychiatry, the former Heidelberg, now Munich, prof. E. Kraepelin put forward a group of mental disorders under the name "dementia praecox" - early or premature dementia.
 Since then, the question of dementia praecox has not left the pages of psychiatric literature; it is dealt with at conferences, special journals are devoted to it, but despite the 20-year existence of the issue, which grew in the Kraepelin's school into a whole doctrine, even now it cannot be considered definitively resolved.