Diagnostic stability over 3 years in a total group of first-episode psychosis patients.

First-episode psychosis (FEP) patients are often given diagnoses that later have to be changed. The aim of this study was to measure the diagnostic stability in a total group of FEP patients; 146 FEP patients were followed longitudinally and prospectively. Their revised baseline diagnoses were compared with their 3-year follow-up diagnoses. The schizophrenic spectrum disorders showed a high diagnostic stability as a group, but there was a great flow of patients between the different schizophrenic spectrum diagnoses. Also schizophrenia was a stable diagnosis. The affective psychosis group was homogenous without interaction of other psychosis groups. The other psychosis diagnoses, both regarded as a group and individually, turned out to be quite heterogeneous, with low stability values and a split course, often ending up in the schizophrenic spectrum. Fifty one per cent did not fulfil the criteria for DSM-IV axis 1 psychosis diagnosis at follow-up. In conclusion, our findings suggest that in the early phase of psychosis. Only three different diagnostic categories would be sufficient; "schizophrenic spectrum type", "affective psychosis," and for the rest "psychotic disorder NOS."