The National Comorbidity Survey (NCS) was conducted to determine the prevalence of mental health disorders in the general population. The investigators chose a nationally representative sample of individuals in different regions of the United States. The predecessor to this study, which also examined mental health prevalence, was the Epidemiologic Catchment Area Study, which was administered to 20,000 individuals in five community epidemiologic surveys. One purpose of the NCS was to expand and improve the survey by examining risk factors and by administering the survey to a larger number of areas in the United States, making it a more representative sample. The investigators also chose a broad-based structured clinical interview, the modified version of the World Health Organization’s Composite International Diagnostic Interview, which could be administered ...