Contradictory issues in the origin of schizophrenia.

In research into the origin of schizophrenia discrepancies repeatedly arise through the habit of treating schizophrenia as an entity. If independent subforms are differentiated, many ambiguities can be cleared up. A special form of catatonia (periodic catatonia) seems to be transmitted by dominant inheritance, a special paraphrenia (affective paraphrenia) recessively. In a large group of schizophrenias (systematic schizophrenias) with a poor outcome family histories of psychosis were rarely found, but examination of twins suggested a psychosocial origin for the disorder. In cycloid psychoses with a benign outcome family histories of psychosis were also seldom found. Only by diagnostic separations can the discrepancies in the field of schizophrenia be solved.