US National Comorbidity Study

The National Comorbidity Survey (NCS) was the first large-scale field survey of mental health in the United States. Conducted from 1990-1992, disorders were assessed based on the diagnostic criteria of the then-most current DSM manual, the DSM-III-R (Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised). The study has had large-scale implications on mental health research in the United States, as no widespread data on the prevalence of mental illness was previously available.

Respondents were reinterviewed in 2001-02 (NCS-2) to study patterns and predictors of the course of mental health disorders and to evaluate the effects of primary mental disorders in predicting the onset and course of secondary substance disorders. At the same time an NCS Replication survey (NCS-R) was carried out in a new national sample of 10,000 respondents in order to study trends in a wide range of variables assessed in the baseline NCS and to obtain more information about a number of topics. A survey of 10,000 adolescents (NCS-A) was also carried out at this so as to produce  nationally representative data on the prevalences and correlates of mental disorders among the young

The NCS-R and NCS-A, finally, are being replicated in a number of countries around the world. Centralized cross-national analysis of these surveys is being carried out by the NCS data analysis team under the auspices of the World Health Organization (WHO) World Mental Health Survey Initiative.

A publically accessible file system containing all the documents from the NCS Program is available and can be accessed over the Internet.

List of papers published by the National Comorbidity Survey

Most notable findings
-The lifetime prevalence of at least 1 mental disorder: 48%

-12 month prevalence of at least 1 mental disorder: 29%

-Comorbidity: Of the people who experience mental illness in their lifetime (48% of pop), 27% will experience more than one. The resulting average is 2.1 mental disorders per (disordered) person.

-Only 40% of people who had ever had a disorder received professional treatment.

-Only 20% of people who had a disorder within the past year received professional help.