Depressive disorders are a chronic, recurrent, and severe burden to both patients and their families. Depressive disorders represent a major national public health problem, ranking within the top 10 most costly diseases in the United States. In 1990, depressive disorders afflicted at least 11 million Americans and cost the U.S. economy an estimated $44 billion. In addition, affective disorders are associated with increased accident rates, increased rates of substance abuse (especially alcoholism), increased medical hospitalization, and an increase in somatic illnesses and outpatient medical utilization. Despite their ranking as a major health problem, depressive disorders are often underdiagnosed and undertreated. Brief treatment strategies that focus only on acute episodes are often ineffective and result in chronic impairment, impairing performance at work and socially. Inadequate treatment increases costs, suffering, and lost productivity. Recent data suggest that effective treatment of depression requires long-term, skillful follow-up and active pharmacotherapy.