Modeling the early course of schizophrenia

Using the Interview for the Retrospective Assessment of the Onset of Schizophrenia (IRAOS), we assessed 170 first illness episodes with a nonpsychotic prodromal stage (73% of the population-based Age, Beginning, Course [ABC] study sample of 232 first illness episodes of schizophrenia from a German population of about 1.5 million). Conrad's (1958) and Docherty et al.'s (1978) stage models of the early course presume unidirectional and compelling patterns of symptom manifestation. Using structural equation modeling, we tested the explanatory power of the stages as latent variables and to what extent these models tally with each other and with data on symptom onset. The models neither converged nor were they confirmed. The reasons for and possible implications of this result will be discussed. We also tested, using various techniques, a causal model of the determinants of social course. The only significant predictors of 5-year social outcome turned out to be social development at psychosis onset and the socially adverse illness behavior of young men. The influence of the traditional predictors, age and gender, type of onset (chronic, acute), and symptomatology, was mediated by these two variables assessed at the end of the prodromal stage.