Depression may be described as feeling sad, blue, unhappy, miserable or down in the dumps. Most of us feel this way at one time or another for short periods. But true clinical depression is a mood disorder in which feelings of sadness, loss, anger or frustration interfere with everyday life for an extended time.
Depression is a common condition. The National Institute of Mental Health (NIMH) estimates that about 10 percent of American adults experience some form of depression. For people with chronic illnesses, the number can be higher. For example, NIMH estimates that about 25 percent of people with cancer have depression, and one study of people with multiple sclerosis found that 41.8 percent had significant symptoms of depression.
The symptoms of depression can be mild, moderate or severe. But even when symptoms are mild, the condition is not the same as temporarily having the blues. People cannot snap out of depression by force of their will. And while practicing healthy habits may help, getting regular exercise, eating right or taking a vacation may not completely alleviate depression.
Depression is more common in women than men and is especially common during the teen years. Men seem to seek help for feelings of depression less often than women. Therefore, women may only have more documented cases of depression.