The concept of cycloid psychosis: the discriminatory power of symptoms

Records of all 154 psychotic patients first admitted to a psychiatric hospital in 1925 were rated according to a checklist of 33 dichotomous items expected to characterize cycloid and schizoaffective psychosis; 64 cases satisfied 5 or more items. Among them, 34 were globally judged as cycloid and showed a favourable outcome when followed up. The remaining 30 cases were used as a contrast sample, consisting of schizoaffective psychotics with an unfavourable outcome and schizophrenics and affective patients who shared some symptoms with the experiment group. Six symptoms significantly more frequent in the cycloid group were all characteristic for confusional and anxiety or happiness psychoses in the sense of Leonhard. Happiness-ecstacy and global altruism were exclusively recorded in cycloid psychosis. A discriminant analysis yielded a significant proportion of correct predictions. The result was thought to be relevant for differential therapeutic strategies.