Mental disorders are common in the United States and internationally. An estimated 22.1% of Americans ages 18 and older-about 1 in 5 adults-suffer from a diagnosable mental disorder in a given year. When applied to the 1998 U.S. Census residential population estimate, this figure translates to 44.3 million people. In addition, 4 of the 10 leading causes of disability in the U.S. and other developed countries are mental disorders - major depression, bipolar disorder, schizophrenia, and obsessive-compulsive disorder. Many people suffer from more than one mental disorder at a given time.
In the U.S., mental disorders are diagnosed based on the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV).
- Depressive disorders encompass major depressive disorder, dysthymic disorder, and bipolar disorder. Bipolar disorder is included because people with this illness have depressive episodes as well as manic episodes.
- Approximately 18.8 million American adults, or about 9.5 percent of the U.S. population age 18 and older in a given year, have a depressive disorder.
- Nearly twice as many women (12.0 percent) as men (6.6 percent) are affected by a depressive disorder each year. These figures translate to 12.4 million women and 6.4 million men in the U.S.
- Depressive disorders may be appearing earlier in life in people born in recent decades compared to the past.