Prevalence and incidence studies of anxiety disorders: A systematic review of the literature

Objective: To present the results of a systematic review of literature published between 1980 and 2004 reporting findings of the prevalence and incidence of anxiety disorders in the general population. Method: A literature search of epidemiologic studies of anxiety disorders was conducted, using Medline and HealthSTAR databases, canvassing English-language publications. Eligible publications were restricted to studies that examined age ranges covering the adult population. A set of predetermined inclusion and exclusion criteria were used to identify relevant studies. Prevalence and incidence data were extracted and analyzed for heterogeneity. Results: A total of 41 prevalence and 5 incidence studies met eligibility criteria. We found heterogeneity across 1 -year and lifetime prevalence rates of all anxiety disorder categories. Pooled 1-year and lifetime prevalence rates for total anxiety disorders were 10.6% and 16.6%. Pooled rates for individual disorders varied widely. Women had generally higher prevalence rates across all anxiety disorder categories, compared with men, but the magnitude of this difference varied. Conclusion: The international prevalence of anxiety disorders varies greatly between published epidemiologic reports. The variability associated with all anxiety disorders is considerably smaller than the variability associated with individual disorders. Women report higher rates of anxiety disorders than men. Several factors were found to be associated with heterogeneity among rates, including diagnostic criteria, diagnostic instrument, sample size, country studied, and response rate.