Depression is a common disorder in later life, when it has a substantial impact, including decreased well-being, decreased daily function, increased mortality, and increased use of health services. Accurate assessment of the natural history of depression in late life is important because the purpose of treatment is to change the prognosis of depression. Depression symptoms tend to fluctuate over time, and the long-term risk for relapse is high. Major depression in late life is rare, but subthreshold depressive disorders are common in that age bracket. Beekman and associates evaluated the natural history of late-life depression, comparing patients who fulfilled vigorous diagnostic criteria with those who did not.

The trial was a portion of the Longitudinal Aging Study Amsterdam that performed a prospective study of the well-being and functioning of community-dwelling older people (55 to 85 years of age). A cohort of depressed persons from this population was identified and followed for up to six years. During the study, each participant was assessed 14 times. This assessment included the administration of the Center for Epidemiological Studies Depression Scale (CES-D) and the Diagnostic Interview Schedule. The natural history of their depression was evaluated for symptom severity and duration, clinical course type, and stability of diagnoses.

The results showed that the average symptom severity score for the CES-D remained above the 85th percentile in the study group. Fourteen percent of the patients had short-lived symptoms, and 23 percent had a remission of their depression. Forty-four percent had an unfavorable and fluctuating course of depression, while 32 percent had a severe, chronic course. Outcomes were more favorable in patients with identified subthreshold disorders, but this group also had an increased risk for developing affective disorders.

The authors conclude that the prognosis for depression in late life is poor, and the burden of depression in these patients is more severe than was previously thought. Subthreshold depression is serious and chronic in many patients. The data show that there is a need to develop strategies that are helpful, acceptable, and economically feasible for addressing this problem in elderly patients.