ABSTRACT
INTRODUCTION In recent years, increasing attention has been directed toward the complex relationships between depression and dementia in the elderly. The predominant research hypothesis has been that depression is a risk factor or even a prodrome for dementia. It is also possible that dementia is a risk factor for depression, that the two disorders share a common etiology, that they are mutually influencing despite separate etiologies, or that their co-occurrence is simply coincidental (1,2). Beyond these theoretical considerations, even the clinical task of distinguishing mood from cognitive symptoms can be a challenge when working with patients whose multiple symptoms, advanced age, medical disease burden, and functional impairment complicate the assessment process. Because both memory complaints and mood complaints are so prevalent among the elderly, a careful and informed process of evaluation and treatment planning is important. This chapter will attempt to shed light on the interrelationships of mood and cognitive disturbances in later life by reviewing normative cognitive changes that occur with aging, examining the varied presentations of depression across the age span and considering biologic, neuroanatomical, and clinical variables affecting the interface between depression and cognition.
