Trajectories of the course of schizophrenia: From progressive deterioration to amelioration over three decades

Background: The extent of heterogeneity in the long-term course of schizophrenia is unclear. Aims: To examine the course of schizophrenia in a population-based cohort. Methods: This study included all Israeli individuals born in 1970-1988, of North African or European origin (N = 2290), entered in the National Psychiatric Hospitalization Case Registry with a last discharge diagnosis of schizophrenia (1978-2004) and followed to 2009. Linked socio-demographic information was extracted from the Population Registry. Based on the number of hospitalized days at each age, trajectory groups were empirically derived, plotted and compared on psychiatric hospitalization measures of the course of illness, social factors and family stressors. Results: Trajectory analysis identified four course groups. Group I (57%) assumed a prototypical course, had an average first hospitalization age of 20, deteriorated until 23 and then ameliorated. Group II (15.5%) assumed an early-onset protracted course, had an average first hospitalization age of 17.1, and deteriorated until 21. Group III (15%) assumed a late-onset with longest deterioration period course, had an average first hospitalization age of 22.7, and deteriorated until 29. Group IV (12%) assumed an early-onset refractory illness course, had an average first hospitalization age of 18, and had the longest hospitalization period. Groups significantly differed on hospitalization (i.e., onset), social (i.e., socioeconomic and ethnic status) and familial factors (i.e., parental death). Despite group differences all deteriorated and then ameliorated on average by the age of 23. Conclusions: The course of schizophrenia was heterogeneous, yet evolved from deterioration to assume a course consistent with amelioration.