The Kraepelinian dichotomy is the division of the major endogenous psychoses into the disease concepts of dementia praecox, which was reformulated as schizophrenia by Eugen Bleuler by 1908,[1][2] and manic-depressive psychosis, which has now been reconceived as bipolar disorder.[3] This division was formally introduced in the sixth edition of Emil Kraepelin's psychiatric textbook Psychiatrie. Ein Lehrbuch für Studierende und Aerzte, published in 1899.[3] It has been highly influential on modern psychiatric classification systems, the DSM and ICD, and is reflected in the taxonomic separation of schizophrenia from affective psychosis.[4] However, there is also a diagnosis of schizoaffective disorder to cover cases that seem to show symptoms of both.