Subsyndromal depression in the elderly: underdiagnosed and undertreated.

Major depressive illness is present in about 5.7% of US residents aged>or=65 years, whereas clinically significant nonmajor or "subsyndromal" depression affects approximately 15% of the ambulatory elderly. Risk of developing subsyndromal depression increases as elderly people get older. Because they have numerous distressing ailments, everyday life can be burdensome for many elderly persons. Almost one third of Americans aged 75 years or older rate their health as "fair to poor." Yet, the physical discomforts experienced by so many elderly individuals are unlikely to generate a clinically significant depression unless other ingredients such as loneliness, impairment of mobility, loss of a spouse, a serious financial reverse, and--probably most important--genetic susceptibility are added to the psychophysiological mix. Because depression damages quality of life and is usually eminently treatable, it is essential that physicians and other health professionals be trained to recognize true depression and distinguish it from confounding conditions caused by medications, organic brain disease, or short-term grief reactions. In the medically ill elderly, depressive symptoms may be overlooked because of the assumption that they are a part of the concurrent medical illness. Diagnosis of depression in the elderly can be greatly assisted by use of age-specific screening instruments such as the Geriatric Depression Scale. Ultimately, brain imaging and biochemical and physiological measurements may prove useful in diagnosis. The presence of somatic concomitants of depression such as severe neck and low back pain should alert the clinician to the possibility of an underlying mood disorder. Suicide and suicide attempts occur all too frequently in the depressed elderly; therefore, screening for late-life depression is urgently required among the elderly in primary and residential health care settings.