DEPRESSIONS are the most common psychiatric condition that clinicians are likely to encounter in adult patients. Public awareness and acknowledgment of depressions and other affective states have increased during the 1970s, and growing numbers of persons with depressive symptoms are seeking medical attention. Epidemiologic studies show that perhaps 15% to 30% of all adults experience depressive symptoms at some time during their lives. Depressions occur about twice as frequently among women as among men and often occur during the highly productive years of young adulthood. The term refers to a mood state, a symptom, or a group of clinical syndromes. Feelings of sadness, disappointment, and frustration are a normal component of the human condition. However, when the sadness interferes with normal functioning, medical intervention may be helpful. Dysphorias may be due to concurrent medical, social, or other psychiatric problems. The syndrome of clinical depression is distinguished from the symptom