The influence of Karl Kleist on the nosology of Karl Leonhard.

Leonhard was largely influenced, during his years at the Frankfurt Mental Hospital, by the Wernicke follower Karl Kleist (1879-1960). Kleist was a representative of brain pathology. His psychopathological concepts, which he developed using the evaluation of brain injuries, look very modern. He tried to attribute different symptoms to definite functional centers and regulatory loops. His theory of the 'autonomous psychic syndromes', his categories of psychomotor activity, his concepts of cycloid psychoses and schizophrenic subgroups are described. The author emphasizes that the differentiation between unipolar and bipolar affective psychoses is based on the team work of Kleist, Edda Neele and Leonhard. Because of Kleist's great contribution to the classification of psychoses, it would be more correct to use the term 'Kleist-Leonhard classification system'.