In addition, some 8.4 million Americans had suicidal thoughts in the past year and 2.2 million made plans to kill themselves. One million attempted suicide, the report found.
Information from other sources confirmed these numbers, with slight variations, the report said.
Dr. John Newcomer, professor of psychiatry and behavioral sciences at the University of Miami Miller School of Medicine, believes the problem may be even bigger than the CDC report indicates.
For example, state Medicaid programs spend a great deal on drugs to treat mental illness, which the CDC didn't take into account, Newcomer said. "For several years the top three drugs were antipsychotic drugs," he noted.
Also, many people with mental illness hide the problem from others, Newcomer said. The CDC report looked at people already in the health-care system, "but there is a big problem with underdiagnosis and undertreatment," he said.
Dr. Alan Manevitz, a clinical psychiatrist at Lenox Hill Hospital in New York City, said healthy living -- getting enough sleep, eating right, exercising -- can help people avoid some mental illness.
"Understanding how to deal with psychological stresses is also important," he said. "How to deal with emotional reactivity and stress tolerances are also important skills to develop early in life."
Manevitz said people should always seek help for mental health troubles whenever "you are not functioning well in your life and isolating yourself."
The U.S. National Institute of Mental Health has more about mental health.
SOURCES: Ileana Arias, Ph.D., principal deputy director, U.S. Centers for Disease Control and Prevention;
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