Depression is a widespread mental health issue and is the general name for a group of depressive disorders. Depression not only affects the inner state of a person, but can also their outward physical functions. In a state of depression, an individual may experience:

• anxiety
• emptiness
• hopelessness
• guilt
• irritability
• restlessness
• sadness

A depressive episode is not just "feeling down," which everyone experiences from time to time. Depression is a chronic and serious health condition that can be medically treated.

(Gale Encyclopedia of Mental Health, 3rd ed.)

DSM-IV and ICD-10 codes are varied. Check the DSM-IV for the correct code.

According to the National Institute of Mental Health's "Major Depression Among Adults" and "Major Depression Among Adolescents:"

• Major depression is one of the most common mental health issue in the U.S.
• In 2014, about 15.7 million (6.7%) adults aged 18 or older in the United States. had at least one major depressive episode in the past year
• In 2014, an estimated 2.8 million (11.4%) adolescents aged 12 to 17 in the United States had at least one major depressive episode in the past year