National Comorbidity Survey (NCS) Series

The National Comorbidity Survey (NCS) was mandated by Congress to survey psychiatric disorders in the United States. It was designed to produce data on the prevalence, risk factors, and consequences of psychiatric morbidity and comorbidity. The NCS was the first nationally representative general population survey of the U.S. to administer a structured psychiatric interview and the first large-scale psychiatric epidemiological survey in the U.S. to use DSM-III-R (American Psychiatric Association, 1987) diagnostic criteria.

National Comorbidity Survey: Baseline (NCS-1) was fielded from 1990-1992 with household sample of over 8,000 respondents, including both persons in the noninstitutionalized civilian population and a supplemental sample of students living in campus group housing. The age range of respondents was 15-54. Subsamples also completed the NCS-1 Part II survey and Tobacco Use Supplement. Diagnoses were based on a modified version of the Composite International Diagnostic Interview (the UM-CIDI), which was developed at the University of Michigan for the NCS-1. The NCS-1 data are available as both public-use and restricted-use files. The restricted-use version contains state and county geography codes.

National Comorbidity Survey: Reinterview (NCS-2) was a reinterview in 2001-2002 of over 5,000 respondents from NCS-1. The survey collected information about changes in patterns of mental disorders and substance use disorders and the predictors and consequences of these changes over the ten years between the two surveys. The study also evaluated the effects of primary mental disorders in predicting the onset and course of secondary substance disorders. Interview questions in the NCS-2 Main Survey were customized to each respondent based on previous responses in the Baseline (NCS-1). The NCS-2 data are available as both public-use and restricted-use versions. The current public-use version does not contain all the sections in the restricted-use version. More information is in the Data Collection Notes.

National Comorbidity Survey Replication (NCS-R) was in 2001-2003 with a new national probability sample of 10,000 English-speaking household residents aged 18 years and older in the coterminous United States. NCS-R was conducted in conjunction with NCS-2. The NCS-R was an in-person survey. The goals of the NCS-R were to study trends in a wide range of variables assessed in NCS-1 and to obtain more information about a number of topics either not covered in NCS-1 or covered in less depth. NCS-R expanded questioning includes assessments based on the more recent DSM-IV diagnostics system (American Psychiatric Association, 1994). To access the data, see the Collaborative Psychiatric Epidemiology Surveys (CPES), that joined data from the NCS-R, the National Survey of American Life (NSAL), and the National Latino and Asian American Study (NLAAS). The NCS-R data are available as both public-use and restricted-use files.

National Comorbidity Survey Replication Adolescent Supplement (NCS-A) was a survey of over 10,000 adolescents in 2001-2004. It was carried out in parallel with the NCS-2 and NCS-R. NCS-A used a dual frame design in which one sample was recruited from the NCS-R households and the other from a representative sample of schools in the same communities as the NCS-R households. It was designed to estimate the lifetime-to-date and current prevalence, age-of-onset distributions, course, and comorbidity of DSM-IV disorders in the child and adolescent years of life among adolescents in the United States; to identify risk and protective factors for the onset and persistence of these disorders; to describe patterns and correlates of service use for these disorders; and to lay the groundwork for subsequent follow-up studies that can be used to identify early expressions of adult mental disorders. Information was also collected from a parent or a parent surrogate that focused on five adolescent disorders for which parental reports are important for making diagnoses. NCS-A is only available as a restricted-use file.