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:
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.