The authors present a literature review and a scientific commentary. The prevalence of depressive disorders in the elderly and their association with significant morbidity and mortality are discussed in relation to study of clinical heterogeneity, which may provide useful insights into etiologic and pathophysiologic variability. The authors summarize findings regarding clinical and associated features of late-life depression, explore the limitations of current factual knowledge and conceptual approaches, and propose directions for future research. They argue that current sample selection procedures minimize the variability of the very phenomena under study; therefore, few phenomenologic differences or risk factors for long-term outcome have been noted consistently. Factors such as medical illness account for much of the observed heterogeneity in presentation and outcome. Future studies must include a broader range of subjects and carefully examine in a multidimensional fashion a wider range of "comorbid" conditions, personality and social assessments, and neuropsychologic and neurobiologic measures. Such approaches will enhance our understanding of the pathophysiologic mechanisms of depression in the elderly and across the lifespan.
Copyright © 1993 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.