12 - Depressive pseudodementia

Summary

Introduction

As life expectancy steadily increases, so do the risks of medical conditions associated with advancing age (e.g. Alzheimer's disease), and more clinical services are now devoted to the physical and mental well-being of older adults (Carpenter, 1996; Grimley-Evans, 1996). With greater public awareness of Alzheimer's disease (AD), demands for better means to identify patients in their earliest stage have intensified (Cooper et al., 1996; Eastwood et al., 1996; Tierney et al., 1996); and with a steady rise in referrals from general practitioners and other agencies, specialist clinics have now been set up to help distinguish them from patients whose cognitive attenuation does not stem from AD (see Chapter 6, this volume; Philpot, 1996; Wright & Lindesay, 1995). One cardinal criterion in the diagnosis of probable AD is the presence of dementia (McKhann et al., 1984), a significant deterioration of neuropsychological functions most evident in the initial phase as memory impairment (Corey-Bloom et al., 1995). But every-day memory in aging individuals can falter for a number of reasons other than AD (e.g. major depressive illness; age-related decline), and research is now carried out to clarify the mechanisms that underlie these ‘amnesic’ states (see Chapter 18, this volume; desRosiers, 1999;McKenna et al., 1998).

Although referred to as pseudodementia, it is now evident the memory lapses often recorded in elderly depressed patients reflect true cognitive difficulties (Beats et al., 1996; Burt et al., 1995; King et al., 1995), but how different these are from deficits brought on by early AD remains uncharted.