Stability of diagnoses in affective, schizoaffective and schizophrenic disorders. Cross-sectional versus longitudinal diagnosis.

The present study investigated the syndrome shift during the course of disease in 355 patients with functional psychoses. The mean observation time was 25.2 years. Every episode was diagnosed cross-sectionally as schizophrenic, melancholic, manic, manic-depressive mixed, schizodepressive, schizomanic or schizomanic-depressive mixed. With regard to the whole course, 148 patients fulfilled the diagnostic criteria of schizophrenic, 106 of affective and 101 of schizoaffective disorders. Patients with a schizophrenic initial episode showed the greatest stability: 90% had no other type of episode. The majority of patients who suffered a melancholic initial episode remained unipolar melancholics or developed manic symptomatology, and only a few suffered schizoaffective or schizophrenic episodes. Patients with a manic symptomatology at the beginning had a very unstable and changeable course. The stability of patients with initial schizodepressive episodes lay between that of patients with melancholic initial episodes and that of those with manic initial episodes. The findings demonstrate the relevance of longitudinal considerations in making the final diagnosis.