Tracing the Roots of Dementia Praecox: The Emergence of Verrücktheit as a Primary Delusional-Hallucinatory Psychosis in German Psychiatry From 1860 to 1880.

While the roots of mania and melancholia can be traced to the 18th century and earlier, we have no such long historical narrative for dementia praecox (DP). I, here, provide part of that history, beginning with Kraepelin's chapter on Verrücktheit for his 1883 first edition textbook, which, over the ensuing 5 editions, evolved into Kraepelin's mature concepts of paranoia and paranoid DP. That chapter had 5 references published from 1865 to 1879 when delusional-hallucinatory syndromes in Germany were largely understood as secondary syndromes arising from prior episodes of melancholia and mania in the course of a unitary psychosis. Each paper challenged that view supporting a primary Verrücktheit as a disorder that should exist alongside mania and melancholia. The later authors utilized faculty psychology, noting that primary Verrücktheit resulted from a fundamental disorder of thought or cognition. In particular, they argued that, while delusions in mania and melancholia were secondary, arising from primary mood changes, in Verrücktheit, delusions were primary with observed changes in mood resulting from, and not causing, the delusions. In addition to faculty psychology, these nosologic changes were based on the common-sense concept of understandability that permitted clinicians to distinguish individuals in which delusions emerged from mood changes and mood changes from delusions. The rise of primary Verrücktheit in German psychiatry in the 1860-1870s created a nosologic space for primary psychotic illness. From 1883 to 1899, Kraepelin moved into this space filling it with his mature diagnoses of paranoia and paranoid DP, our modern-day paranoid schizophrenia.