In 2007, 16.5 million American adults (close to 8 percent of the population) suffered at least one episode of major depression, and less than two thirds of them (65 percent) received treatment. According to the DSM - 5, a person is suffering from a major depressive episode if he or she experiences items 1 or 2 from the list of symptoms below, along with any four others, continuously for more than two weeks:

  1. Depressed mood with overwhelming feelings of sadness and grief
  2. Apathy—loss of interest and pleasure in activities formerly enjoyed
  3. Sleep problems—insomnia, early-morning waking, or oversleeping nearly every day
  4. Decreased energy or fatigue
  5. Noticeable changes in appetite and weight (significant weight loss or gain)
  6. Inability to concentrate or think, or indecisiveness
  7. Physical symptoms of restlessness or being physically slowed down
  8. Feelings of guilt, worthlessness, and helplessness
  9. Recurrent thoughts of death or suicide, or a suicide attempt.

The diagnosis is more certain when a person also has a family history of depression, has had a previous episode of depression or bipolar disorder, has a general medical problem likely to trigger depression (such as a recent stroke or heart attack), or is taking a medication known to cause mood disorders.

Other symptoms of depression may include disorganized thinking and delusions. In addition to these disturbances in mood and cognition (thinking), people with major depression may experience physical changes such as constipation or decreased sexual drive.

Episodes of major depression range from mild to severe. In mild episodes, symptoms barely meet the requirements for a diagnosis and the person is able to get through the day without much trouble. Severe episodes are characterized by several debilitating symptoms, including worsening mood that markedly interferes with daily life. People who are struggling with severe depression have difficulty with almost every activity—going to work, socializing, and even getting up in the morning. In the most severe cases, depressed individuals may be unable to feed and dress themselves or to maintain personal hygiene.

Major depression is believed to be twice as common in women as in men, although that statistic is now being questioned; in fact, depression symptoms may be different in men and women, as well as in older versus younger people. Men are more inclined to get angry and irritable, feel an increasing loss of control over their lives, take greater risks, become more aggressive, and complain about problems at work rather than feeling sad, weepy, worthless, or guilty, as women usually do.

Updated by Remedy Health Media

Publication Review By: Karen L. Swartz, M.D.

Published: 01 Mar 2011

Last Modified: 02 Dec 2014