Anxiety and the schizophrenic process: clinical and epidemiological evidence

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. Method: 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. Conclusion: 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.