batteries. Further, test selection should be based on key psychometric properties,
including sensitivity to subtle individual differences and lack of ceiling effects. Our
understanding of SMC may be better served by use of the term“subjective cog-
nitive complaints”in self-report measures and by a more nuanced evaluation of
subtypes of cognitive complaints, such as SMC, subjective attention complaints,
and subjective language complaints.
Several conceptual issues may also account for discrepancies in the literature.
Early work on SMC was criticized for not considering important covariates, such as
depression and sleep. Later work has addressed this limitation, typically through
statistical adjustment. But is such statistical adjustment justified? Or, does statistical
adjustment overcorrect for a true relationship between SMC and objective perfor-
mance in the context of low mood? How much of the relationship between SMC and
memory performance in a person with low mood reflects heightened self-criticism
and how much reflects a valid rating of a cognitive symptom of depression? It is
often argued that SMC reflect depression rather than actual memory performance,
but diminished ability to think or concentrate is a core symptom of depression, and
depression causes memory dysfunction. Thus, the relationship between these two
constructs does not invalidate SMC, but perhaps demonstrates that SMC as a core
feature of depression relates to cognitive functioning. This is particularly relevant in
older adults, as depression is an independent risk factor for dementia. Similarly,
stress and sleep difficulties are often related to SMC, but these also independently
impact cognitive function. Our understanding of how SMC relate to objective
cognitive function would be improved by examining patterns of cognitive function
and their underlying neuroanatomical substrate. For instance, stress, sleep disrup-
tion, and depression may impact attentionally mediated cognitive processes and
memory retrieval, whereas hippocampal atrophy may impact memory retention.
Functional neuroimaging studies may be particularly useful in this regard.
A neglected issue is how the relationship between SMC and objective cognitive
performance might differ across culture, race, and ethnicity. The large majority of
studies have been conducted on samples comprised primarily of people of European
descent from the USA and Western Europe. Within those studies, race has rarely
been examined as a variable of interest. One study that specifically compared
African American and European American older adults found that African
Americans were less likely to report memory deterioration, but showed greater
objective cognitive decline (Blazer et al. 1997 ). Generalizability of currentfindings
to other cultures and races is unknown. Generalizability to individuals with low
levels of education is particularly problematic as most validated tests of objective
cognitive function are influenced by education and require a basic level of literacy.
An small study of SMC in a rural and largely illiterate population in the Amazon
rain forest found the prevalence of SMC to be much higher than that reported in
studies in developed nations (70%), but found the correlates of SMC to be similar
(somatic and psychiatric symptoms, worse overall cognitive function) (Brucki and
Nitrini 2009 ). Clearly, much more work is needed to examine whether the rela-
tionship between SMC and objective cognitive performance differs across races,
ethnicities, and cultures.
294 M.T. Weber and P.M. Maki