Secondary depression is a depression in an individual who has one or more preexisting, nonaffective psychiatric disorders or an incapacitating or life-threatening medical illness which precedes and parallels the symptoms of depression. Secondary depression is commonly seen in patients presenting to psychiatric facilities. For every 5 patients who are seen with a diagnosis of depression, approximately 2 should be classified as secondary. A patient with secondary depression is more likely to be younger, male, and to have a family history of alcoholism. His first diagnosis is most likely to be alcoholism; however, the preceding diagnosis varies depending on the setting in which the patient is seen. Hysteria, sociopathy, drug abuse and anxiety neurosis are also common. The symptom picture of secondary depression is almost indistinguishable from primary depression. One important reason a patient enters psychiatric treatment is that he develops a coexistent depression.