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	Since this article does not have an abstract, we have provided the first 150 words of the full text and any section headings.

I read with interest the study on the relationship between depression and mortality in the October issue of the ARCHIVES.¹ Studies of mental illness in older adults are urgently needed due to the aging of our population. The inclusion in this study of explanatory variables measuring the health and health behaviors of the participants made the study just that much more valuable.

I wondered whether a misspecification bias might have been introduced into the study when the investigators did not include cognitive impairment along with chronic diseases as a possible confounding variable. The inclusion of stroke and peripheral atherosclerosis would account for some cases of cognitive impairment. However, dementing illnesses such as Alzheimer disease may have contributed to the mortality rate as well. Also, according to the terminal drop hypothesis, a rapid diminishment of cognitive functioning marks the 5 years preceding death in elderly people.² Inclusion of cognitive functioning as . . . [Full Text of this Article]