Every year, about 42.5 million American adults (or 18.2 percent of the total adult population in the United States) suffers from some mental illness, enduring conditions such as depression, bipolar disorder or schizophrenia, statistics released Friday reveal.

The data, compiled by the Substance Abuse and Mental Health Services Administration (SAMHSA), also indicate that approximately 9.3 million adults, or about 4 percent of those Americans ages 18 and up, experience “serious mental illness” - that is, their condition impedes day-to-day activities, such as going to work.

This data does not diverge greatly from the last SAMHSA report, released in 2012, which found that 45.9 million American adults, 20 percent of this demographic, experienced mental illness at least once annually. (Though there is a 1.8 percent difference, the statistics do have margins of error, and methods of compiling them are often revised, so this dip does not necessarily mean there has been a long-term decline in mental illness.)

Mental disorders are common in the United States and internationally. An estimated 26.2 percent of Americans ages 18 and older or about one in four adults suffer from a diagnosable mental disorder in a given year. When applied to the 2004 U.S. Census residential population estimate for ages 18 and older, this figure translates to 57.7 million people.

Even though mental disorders are widespread in the population, the main burden of illness is concentrated in a much smaller proportion about 6 percent, or 1 in 17 who suffer from a serious mental illness. In addition, mental disorders are the leading cause of disability in the U.S. and Canada for ages 15-44. Many people suffer from more than one mental disorder at a given time. Nearly half (45 percent) of those with any mental disorder meet criteria for two or more disorders, with severity strongly related to comorbidity.

In the U.S., mental disorders are diagnosed based on the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV).

Mood Disorders
Mood disorders include major depressive disorder, dysthymic disorder, and bipolar disorder.

•   Approximately 20.9 million American adults, or about 9.5 percent of the U.S. population age 18 and older in a given year, have a mood disorder.
•   The median age of onset for mood disorders is 30 years.
•   Depressive disorders often co-occur with anxiety disorders and substance abuse.

Suicide

•   In 2004, 32,439 (approximately 11 per 100,000) people died by suicide in the U.S.7
•   More than 90 percent of people who kill themselves have a diagnosable mental disorder, most commonly a depressive disorder or a substance abuse disorder.
•   The highest suicide rates in the U.S. are found in white men over age 85.
•   Four times as many men as women die by suicide; however, women attempt suicide two to three times as often as men.

Schizophrenia

•   Approximately 2.4 million American adults, or about 1.1 percent of the population age 18 and older in a given year, have schizophrenia.
•   Schizophrenia affects men and women with equal frequency.
•   Schizophrenia often first appears in men in their late teens or early twenties. In contrast, women are generally affected in their twenties or early thirties.