[The concept of negative and positive symptoms in a historical perspective].

Over the last years, the modern psychopathological classification of schizophrenic symptoms into the groups of negative and positive symptoms has gained more relevance to the diagnosis, therapy and prognosis of this disorder. We delineate the historical concept of negative and positive elements, which was developed by the British neurologist John Hughlings Jackson (1835-1911) to explain the pathophysiology of psychic disorders. These definitions are elucidated in view of the scientific context at the end of the 19th century, when evolutionism, positivism, psycho-physical parallelism, and the knowledge of neurosciences played an important part. In addition, the reception of Jackson's ideas by psychiatry is shown. Freud was essentially influenced by Jackson in developing his psychoanalytical theory of neurosis. Bleuler joined Freud and defined "primäre" and "sekundäre" symptoms of schizophrenia. In the phenomenological concept of schizophrenia of Huber, "Basissymptome" are distinguished from "End- und Uberbausymptome", which in part correspond to the negative and positive symptoms of today, respectively. The paper provides a historical survey of the Jacksonian influences on concepts of schizophrenia.