The disorder depression is a feeling of sadness intense enough to interfere with functioning and/or a decreased interest or pleasure in activities. It may follow a recent loss or other sad event but is out of proportion to that event and lasts beyond an appropriate length of time.
Heredity, side effects of drugs, emotionally distressing events, changes in levels of hormones or other substances in the body, and other factors can contribute to depression.
Depression can make people sad and sluggish and/or lose all interest and pleasure in activities they used to enjoy.
Doctors base the diagnosis on symptoms.
Antidepressants, psychotherapy, and sometimes electroconvulsive therapy can help.
People often use the term depression to describe the sad or discouraged mood that results from emotionally distressing events, such as a natural disaster, a serious illness, or death of a loved one. People may also say they feel depressed at certain times, such as during the holidays (holiday blues) or on the anniversary of a loved one's death. However, such feelings do not usually represent a disorder. Usually, these feelings are temporary, lasting days rather than weeks or months, and occur in waves that tend to be tied to thoughts or reminders of the distressing event. Also, these feelings do not substantially interfere with functioning for any length of time.
After anxiety, depression is the most common mental health disorder. About 30% of people who visit a primary care practitioner have symptoms of depression, but fewer than 10% of these people have major depression.
An episode of depression, if untreated, typically lasts about 6 months but sometimes lasts for 2 years or more. Episodes tend to recur several times over a lifetime.