Section 1: Mental health and disability: Definitions and prevalence
1.6. How many people have a serious mental illness?
Serious mental illness is a broader category of mental disorders that includes severe mental illness. The term serious mental illness is used to distinguish mental disorders that cause disability from mental disorders that do not result in disability. Under the Alcohol, Drug Abuse, and Mental Health Administration (ADAMHA) Reorganization Act of 1992, serious mental illness was defined as having any DSM mental disorder that leads to "substantial interference with one or more life activities." Specifically, serious mental illness included people whose disorder substantially interfered with their vocational capacity, created serious interpersonal difficulties, or was associated with a suicide plan or attempt.
It is estimated that about 10 million people (5.4% of the non-institutionalized civilian U.S. population 18 years and older) have a serious mental illness. Adding synthetic estimates for people in correctional institutions, nursing homes and other institutions, military personnel and homeless people, brings the overall estimate to 12.2 million people with serious mental illness.
Over 12 million adults in the U.S. have a serious mental illness.
Figure 6: Estimates of U.S. adults 18 years and over, with serious mental illness, and with no serious mental illness, 1990
Source: Kessler, Berglund, et al. (1998)
Surveys: National Cormorbidity Survey (NCS, 1990-92); Epidemiologic Catchment Area (ECA, 1980-85) and other surveys