[The diagnosis "schizophrenia": past, present and future]

Schizophrenia is one of the most important diseases in psychiatry. The diagnostic criteria, first formulated more than 100 years ago, have since undergone multiple changes. While the disease was originally named "dementia praecox" by Emil Kraepelin, the term "schizophrenia" was coined by Eugen Bleuler soon afterwards. DSM-III changed diagnostic criteria dramatically in 1980, relying especially on Kurt Schneider's first rank criteria. These changes were also incorporated into ICD-10. Diagnosis of schizophrenia thus became much more reliable. Yet there remain many problems to be solved: the demarcation towards other psychotic disorders remains arbitrary; the diagnosis is based on multiple, quite different symptoms, enabling two patients being diagnosed with schizophrenia without sharing a single symptom, yet further important symptoms (e.g. cognitive impairments) are not even covered by present diagnostic criteria; until now it was not possible to formulate diagnostic criteria reflecting underlying biological processes or to find a reliable biological marker. These methodological uncertainties are in stark contrast to the persistence of the stigma which accompanies schizophrenia despite all efforts. For the forthcoming publication of DSM-5 and ICD-11 further revisions of diagnostic criteria of schizophrenia are to be expected.