title: Readmission risk in schizophrenia: selection explains previous findings of a progressive course of disorder.
abstract: BACKGROUND
  Several studies have investigated the issue of the natural course of schizophrenia. Our study addressed whether there is evidence for progression, potentially deteriorating, over the long-term course of the disorder.
  
  
  METHODS
  Modern survival analysis techniques were applied to case-register data on the pattern of readmission to in-patient psychiatric facilities. The sample consisted of a total of 8953 persons with schizophrenia.
  
  
  RESULTS
  No evidence of a progressive course of schizophrenia was found in the present study. The accelerating pattern of the course of schizophrenia described by some authors, including a previous analysis of an almost identical dataset, can be explained by selection.
  
  
  CONCLUSIONS
  Heterogeneity reflecting the various levels of individual vulnerability may govern the overall individual course of schizophrenia. We hypothesize that the persistent deficit syndrome and negative symptoms are influential determinants of this heterogeneity.
authors.affiliation: Department of Psychiatric Demography, Risskov, Denmark.
authors.forename: A V
authors.initials: AV
authors.lastname: Olesen
authors.forename: P B
authors.initials: PB
authors.lastname: Mortensen
mesh_terms: D000328:Adult; D001330:Electronic Data Processing; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization; D006778:Hospitals, Psychiatric / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010359:Patient Readmission / Q000706:statistics & numerical data*; D011446:Prospective Studies; D012307:Risk Factors; D012559:Schizophrenia / Q000453:epidemiology* / Q000534:rehabilitation*; D013997:Time Factors