title: Anxiety and the schizophrenic process: clinical and epidemiological evidence.
abstract: BACKGROUND
  The authors hypothesise that anxiety is an integral part of the development of schizophrenia in a significant sub-group of cases. This paper reviews the evidence for an epidemiological link between anxiety and schizophrenia, emphasising those studies that imply a temporal sequence.
  
  
  METHODS
  An augmented systematic search of electronic databases was conducted, and the methods and results of the studies identified were reviewed.
  
  
  RESULTS
  Panic disorder was identified in around 20% of cases of schizophrenia in clinical studies (range 5-33 %). Other anxiety disorders were less often studied, but were also frequent. Epidemiological studies from the Epidemiological Catchment Area Program confirm the strong association between anxiety disorders and schizophrenia. Finally, cohort studies identify anxiety as an early antecedent of schizophrenia.
  
  
  CONCLUSIONS
  There is a significant link between anxiety and schizophrenia. This may represent a psychological process integral to an appreciable number of cases of schizophrenia. Focused psychological studies are needed to determine whether this is so.
authors.affiliation: Royal Free and University College Medical School, University College London, Department of Psychiatry and Behavioural Sciences, Whittington Hospital, London, UK.
authors.forename: G
authors.initials: G
authors.lastname: Turnbull
authors.forename: P
authors.initials: P
authors.lastname: Bebbington
mesh_terms: D001008:Anxiety Disorders / Q000453:epidemiology* / Q000235:genetics; D002986:Clinical Trials as Topic; D015331:Cohort Studies; D015897:Comorbidity / Q000639:trends; D020022:Genetic Predisposition to Disease; D006801:Humans; D016584:Panic Disorder / Q000453:epidemiology; D012559:Schizophrenia / Q000453:epidemiology* / Q000209:etiology / Q000235:genetics; D012565:Schizophrenic Psychology; D006113:United Kingdom / Q000453:epidemiology