Depression in the elderly. I. Relationship between depression, psychologic defense mechanisms and physical illness.

Diagnosis of depression in the elderly is sometimes difficult owing to the presence of ego defensive mechanisms or somatic symptoms that can disguise the affect. Depression also may precede, or be associated with a variety of medical illnesses which are common among older persons. Specific ego defenses and representative medical illnesses are discussed. The concepts of a depressive equivalent and pseudodementia, which particularly act to disguise the depression, are reviewed in detail.