[Medical and ethical problems in the classification of psychiatric disorders. The "Wurzburger Schlussels" of 1933].

In 1930 a new classification of mental disorders, later on known as "Würzburger Schlüssel", was developed and tested for two years. It replaced the "Reichsirrenstatistik" from 1901, and included new disease entities. This pragmatical classification was mainly descriptive including a few elements regarding aetiology and course of disease. The "Würzburger Schlüssel" put emphasis on addictions (especially alcoholism), psychopathy (in teenagers as well as in adults) and on the sequelae of syphilis. However, most of the diseases in elderly patients were not classified as being due to the various descriptive disease entities, but to the age related category. The fundamental problems of the development and practice of a classification of psychic disorders and the accompanying medical and ethical problems, which are still important today, are discussed.