Depression is a major public health problem associated with increased functional disability and mortality. The annual economic consequences of depression were estimated at 83 billion dollars in the United States in 2000  and 118 billion euro in Europe in 2004 .
The epidemiology, pathogenesis, and neurobiology of depression in adults are reviewed here. The clinical features, diagnosis, treatment, and prognosis of depression are discussed separately.
●(See "Unipolar depression in adults: Assessment and diagnosis".)
●(See "Unipolar major depression in adults: Choosing initial treatment".)
●(See "Unipolar depression in adults: Treatment of resistant depression".)