Depression in the United States Household Population, 2005–2006

Depression is a common and debilitating illness. It is treatable, but the majority of persons with depression do not receive even minimally adequate treatment (1). Depression is characterized by changes in mood, self-attitude, cognitive functioning, sleep, appetite, and energy level (2). The World Health Organization found that major depression was the leading cause of disability worldwide (3). Depression causes suffering, decreases quality of life, and causes impairment in social and occupational functioning (4). It is associated with increased health care costs as well as with higher rates of many chronic medical conditions (5). Studies have shown that a high number of depressive symptoms are associated with poor health and impaired functioning, whether or not the criteria for a diagnosis of major depression are met (6,7).