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 prevelence of mental illness was previously available.

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.