Objective: The aim of this study was to compare indicators of outcome between different types of psychosis and to verify whether or not negative symptoms (NS) have a special relevance for schizophrenia.
Method: This is a follow-up study on functional psychosis according to ICD-9. Patients were assessed standardized at the time of first hospitalization and about 12.5 years later.
Results: Comparison of global outcome parameters and NS revealed that schizophrenia had the poorest outcome of all types of psychosis. NS had the highest impact on global functioning and the severity of illness in schizophrenia. NS assessed at the first hospitalization were associated with the different outcome parameters only in schizophrenia at follow-up.
Conclusion: The course of schizophrenia is a more deteriorating one than that of affective or schizoaffective psychosis. The findings point to the special relevance of NS for the outcome and their relative specificity for schizophrenia.