Kurt Schneider's 'Zwischen-Fälle', 'mid-cases' or 'cases in between'.

Kurt Schneider's concept recognizes an intermediate area between the two groups of the major psychoses: the 'Zwischen-Fälle', in translation 'mid-cases' or 'cases in between'. We investigated 108 such cases, and we found that some features external to the symptomatology distinguished the 'mid-cases' or the 'cases in between' from schizophrenia and suggested particular similarities to the affective psychoses. Such external factors were: age, heredity, educational and occupational level, broken home situation, life events, and necessity for long hospitalization.