Mental Illness Common in the U.S.

More Than 1 in 4 Adults Per Year Affected By Mental Illness or Substance Abuse

From the WebMD Archives

June 6, 2005 -- New research shows that mental illness is common in the U.S., but many people don't get prompt, adequate treatment.

More than one in four U.S. adults per year have some form of mental illness or substance abuse. Many of those cases are mild, but 14% of the population has moderate or severe mental illness, say Harvard Medical School's Ronald Kessler, PhD, and colleagues.

Lifetime prevalence is even higher. About half of all Americans will meet the criteria for some type of mental disorder sometime in their lifetime, with first onset usually in childhood or adolescence, Kessler writes in June's Archives of General Psychiatry.

"Most people with mental disorders in the United States remain either untreated or poorly treated," write researchers in another study in the journal.

Mental Illness Is Treatable

Before you read another word, know this: Mental illnesses can be treated. Health experts urge people to seek care if their moods, substance use, or thinking is suffering.

When in doubt, ask. Doctors and counselors can help find and treat the problem. While the new studies only included adults, nurturing children's mental health is obviously also important.


It's normal to have ups and downs. Mental illness goes beyond that, dragging people down to a shadow of their true selves. Those problems are nothing to be ashamed of and deserve swift attention, just like any other health condition.

"People with mental illnesses can be treated effectively and lead normal, productive lives," says former first lady and mental health advocate Rosalynn Carter.

Tracking Mental Illness

The new studies are based on face-to-face interviews with more than 9,200 English-speaking adults. Homeless people and those in institutions were not included.

The findings showed that during the course of a year, 26% had any mental disorder, including substance abuse. Anxiety was the most common problem, seen in 18% of the participants. Next were mood disorders (9.5%), impulse control problems (9%), and substance disorders (3.8%).

About 40% of those cases were mild, while 37% were "moderate" and 22% were "serious," say Kessler and colleagues. Severity included the degree of disability and suicide plans or attempts.

"Although mental disorders are widespread, serious cases are concentrated among a relatively small proportion of cases with high co-morbidity [more than one illness]," says the study.

Lifetime Patterns of Mental Illness

Kessler's team also estimated lifetime prevalence. They say that nearly three in 10 (29%) will develop anxiety disorders at some point in their lives, making it the most common mental illness.

Other lifetime estimates were 21% for mood disorders such as depression, 25% for impulse-control disorders, and nearly 15% for substance disorders. That amounts to a 46% risk for any of those disorders, says the study.

On average, most people with anxiety and impulse-control disorders develop those problems at age 11, says the study. That's "much earlier" than average ages for substance use (20 years) and mood disorders (30 years), write the researchers.

"Half of all lifetime cases start by age 14 years and three-fourths by age 24 years," they say.

Treatment Often Poor

A lot of people don't seek immediate treatment and don't get adequate care, according to the interviews.

Less than half (41%) of those who experienced mental illness over the course of a year sought treatment during that time. That included treatment from psychiatrists, mental health specialists who aren't psychiatrists, general medical care providers, human services providers, and providers of complementary and alternative medicines.


"Of treated patients with disorders, only 32.7% were classified as receiving minimally adequate treatment," says the study by Harvard Medical School's Philip Wang, MD, DrPH.

Adequate treatment was defined as at least two months of an appropriate medication plus more than four visits to any type of physician, or eight or more visits with any health care or human services provider.

Many Delay Treatment

"The vast majority of people with lifetime disorders eventually make treatment contact, although more so for mood disorders than for anxiety, impulse control, or substance disorders," write Wang and colleagues.

But many wait years or even decades before seeking help. "Delay among those who eventually make treatment contact ranges from six to eight years for mood disorders and 9 to 23 years for anxiety disorders," write researchers.

Those who don't seek help or delay treatment are more likely to be older, male, married, poorly educated, racial/ethnic minorities, and those whose problems started at a young age.

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SOURCES: Kessler, R. Archives of General Psychiatry, June 2005; vol 62: pp 593-602 and pp 617-727. Wang, P. Archives of General Psychiatry, June 2005; vol 62: pp 603-613 and pp 629-640. WebMD Live Events Transcript: "Mental Illness in America," May 21, 2004. News release, JAMA/Archives.

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