The survey by the Substance Abuse and Mental Health Services Administration found women were more likely than men (23 percent to 16.8 percent) to have experienced a mental illness, while the rate of mental illness among people aged 18 to 25 was twice that of those aged 50 and older.

The administration defined mental illness among adults as diagnosable mental, behavioral or emotional disorders, excluding developmental disorders and substance use.

The survey found that 5 percent of American adults, or 11.4 million people, had suffered a serious mental illness in the past year that substantially interfered with their lives.

The report found that about 8.7 million American adults had serious thoughts of suicide in the past year, with 2.5 million making suicide plans and 1.1 million attempting to take their own lives.

Americans suffering mental illnesses were three times as likely to have developed substance dependence or substance abuse disorders than adults who had not experienced mental illness.

Among youths aged 12 to 17, 8 percent -- or 1.9 million teenagers -- experienced a major depressive episode in the past year, defined as a period of at least 2 weeks when a person experienced a depressed mood or loss of interest.

Those teenagers who experienced a depressive episode also had twice the rate of illicit drug use than teenagers who had not experienced depression.

The administration surveyed 67,500 people aged 12 and older in person around the United States.

(Reporting by Michelle Nichols; Editing by Daniel Trotta and Todd Eastham)

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