(Pearman and Storandt 2004 ). They are also associated with negative affect
(Derouesne et al. 1999 ), lower physical functioning (Comijs et al. 2002 ), sleep
disturbance (Weber et al. 2012 ), and stress (Elfgren et al. 2010 ), all of which have
been independently associated with cognitive performance (Reid et al. 2012 ;
Walker 2008 ). Many studies suggest a sex difference in SMC, with women per-
ceiving more memory problems than men (Gagnon et al. 1994 ). Higher levels of
education are associated with fewer SMC and better objective memory performance
(Bassett and Folstein 1993 ). Given the frequency of such complaints, there is great
interest in the possible clinical relevance of SMC as a sign of underlying disease or
change in brain function, but their significance is not entirely known. The literature
addressing this issue is mixed, and questions remain about whether or not indi-
viduals are generally able to accurately assess their own memory abilities.
In middle-aged adults, SMC are generally thought to reflect underlying psycho-
logical dysfunction, such as depression or anxiety, sleep disturbance, or stress, rather
than neurologic dysfunction. This is because memory disorders such as Alzheimer’s
disease are very rare atmidlife.Itis now wellrecognizedthat psychological dysfunction
negativelyaffectsmemoryandothercognitivefunctions.Further,theneuropathological
processes that characterize Alzheimer’s disease begin at midlife, a decade or more
before the onset of dementia. Thus, for individuals at midlife and beyond, there is
concern that SMC may reflect the beginning of a true decline in cognitive and/or brain
function. The menopausal transition is often accompanied by both subjective and ob-
jective changes in memory function (Mitchell and Woods 2001 ; Greendale et al. 2009 ;
Eppersonet al. 2013 ), withnearlytwo-thirdsof womenreporting anundesirable change
inmemoryfunction(Mitchell and Woods 2001 ).Ingeneral,there are few investigations
that have systematically compared SMC with concurrent objective memory perfor-
mance in young and middle-aged adults. However, memory changes are thought to
occur across all of adulthood (Zacks et al. 1999 ).
In older adults, SMC are often thought to be an early marker of cognitive decline
or dementia. They are a core feature of the diagnostic criteria for mild cognitive
impairment (MCI), an intermediate condition between normal aging and dementia.
This criterion assumes that SMC can serve as a proxy for objective memory decline.
Data supporting this assumption is mixed, with some studies demonstrating that
individuals with SMC perform more poorly on objective memory tests than those
without complaints, whereas other studies demonstrate that SMC relate only to
depression and other forms of psychological distress (see Reid and MacLullich
2006 ; Roberts et al. 2009 ; Stewart 2012 for reviews). SMC have also been shown to
relate to cognitive functions other than memory, such as attention (Scholtissen-In de
Braek et al. 2011 ; Weber et al. 2012 ; Drogos et al. 2013 ). Neuroimaging studies
show a relationship between SMC and brain structure and function (see Stewart
2012 for review). However, many patients with Alzheimer’s disease fail to rec-
ognize their cognitive declines and deny memory problems. Thus, SMC are used as
13 Subjective Memory Complaints and Objective Memory Performance 277