[Model concepts of the interaction of biological and psychosocial factors in schizophrenia].

On the basis of the current research, his own contributions and complementary theoretical considerations, the author develops four possible models on the causal relations between biological and psychosocial factors in schizophrenia, namely 1. a biological-psychosocial model, 2. a psychosocial-biological model, 3. a parallelist- or multilevel-model and 4. a circular model. According to the latter as currently most probable model, variable interactions between biological and psychosocial factors lead to a premorbid vulnerability with lowered information processing capacities and increased tendencies to psychotic functioning under stress. Equally, variable interactions between different biological and psychosocial factors furnish the best explanation for the enormous multiformity and nearly unforeseeable variability of the long-term evolutions. The circular model is also particularly fruitful for therapeutic purposes.