Less than half of the 4 million adults estimated to have serious mental illness and a co-occurring substance use disorder in 2002 received treatment for either problem, according to a June report from the Substance Abuse and Mental Health Services Administration (SAMHSA).

The data, which come from the 2002 National Survey on Drug Use and Health, a household survey of 44,481 randomly selected adults in the United States, found that an estimated 17.5 million adults aged 18 or older had a serious mental illness during the preceding year, or about 8 percent of all adults in the country.

Furthermore, about 4 million, or 23 percent, of adults with mental illness in 2002 were also dependent on or had abused illicit drugs and/or alcohol.

In contrast, among adults without a serious mental illness, only about 8 percent acknowledged dependence on or abuse of drugs or alcohol.

The researchers defined serious mental illness as a "diagnosable mental, behavioral, or emotional disorder that met DSM-IV criteria during the previous year that resulted in functional impairment that substantially interfered with one or more major life activities." (They separated substance use from other mental disorders for the purposes of this study.)

One striking finding was that a little over half (52 percent) of those with mental illness and a co-occurring substance use disorder received neither mental health nor specialty addiction treatment during the year prior to the survey.

These were among the findings on the 4 million adults with co-occurring disorders:

Findings from the 2002 National Survey on Drug Use and Health are posted online at<www.oas.samhsa.gov>.▪