The current study expands on findings in the self-appraisal literature by addressing the ways in which depression and cognition influence and mediate self-reported IADL functioning (i.e., medication management and driving), and whether objective measurements confirm these self-reports in an HIV-infected sample.
Our results demonstrate that individuals with depressive symptoms tend to inaccurately over-report cognitive and functional impairments. Specifically, those who over-reported cognitive and functional deficits demonstrated the highest levels of depression relative to other appraisal groups. Alternatively, individuals who under-reported deficits in cognitive and functional abilities reported the lowest levels of depression. Although neurocognitive functioning was strongly related to performance on driving and medication management, depression was not, suggesting that poor performance on laboratory-based measures of functional abilities are more sensitive to cognitive deficits than mood status. As previously discussed, we were unable to subdivide accurate self-reporters into functionally unimpaired and impaired groups due to the small cell sizes of participants whose self-reported functional impairments were confirmed by functional performance; that is, a majority of accurate self-reporters demonstrated normal functional performance. Because we were unable to make comparisons between under-reporters and participants who accurately reported impairments, it was not possible to establish whether poor cognition results in a “true” lack of awareness of functional deficits in medication management and driving.
Nonetheless, we examined differences in cognitive functioning between participants who consistently under-reported, over-reported, and were accurate in their self-assessments of functional abilities (i.e., medication management and driving). We found that under-reporters were more cognitively impaired than over-reporters and accurate self-assessors, suggesting that cognitive impairment may play an even greater role in self-report of functional abilities. Our findings related to depression were consistent across all analyses, thereby indicating that depressive symptoms are more likely to lead to inaccurate self-report of functional deficits than neuropsychological functioning. Moreover, our participants were not formally diagnosed with depression; rather they presented with a range of depressive symptoms. This suggests that a clinical diagnosis of depression is not necessary for overestimations of functional disability to occur. As a whole, our sample of participants demonstrated normal to mildly impaired levels of cognitive functioning. It remains possible that only at greater levels of cognitive impairment does diminished awareness of functional deficits become more apparent, which is consistent with findings from Marcotte and colleagues (2004)
demonstrating that a subset of HIV+ drivers who failed the on-road driving simulator were unaware of their poor performance.
This study found that depressive symptoms, learning and memory, attention/working memory, information processing speed, language, motor functioning, and executive functioning most accurately classified over-reporters and under-reporters, which is consistent with previous studies that have linked these domains to impaired awareness suggesting dysfunctions in frontal circuitry, as well as HIV-associated cognitive impairment. This finding highlights the importance of these cognitive and psychiatric variables when predicting the ability to provide accurate self-report of functional abilities.
Consistent with expectations, there were no significant relationships between self-reported functional abilities and objective functional task performance. Considering the previous findings, it is plausible that psychiatric factors and cognition may account for the lack of relationship in self-appraisal and awareness of functional abilities. Our findings are in accordance with previous studies linking discrepancies between subjective ratings versus objective neuropsychological performance with depression among individuals with HIV (Carter et al., 2003
; Heaton, Marcotte et al., 2004
; Hinkin et al., 1996
; Moore et al., 1997
; van Gorp et al., 1991
We recognize that laboratory-based measures of functional capacity may not fully represent actual functional abilities, so the extent to which we can make inferences about functional capacity is limited. Future investigations comparing performance on functional measures to real-world performance (e.g., comparing simulated driving performance to on-road driving, such as was done by Marcotte et al., 2004
) would help to clarify the accuracy of performance-based functional measures. Although we did not have access to informant ratings in this study, comparing informant ratings to functional performance would also help to address the predictive value of these functional measures.
Despite these limitations, several interesting results from the current study have implications for working with individuals infected with HIV. First, our findings suggest that the neurocognitive and psychiatric aspects of HIV/AIDS are largely independent of one another (Grant et al., 1993
; Hinkin et al., 1992
; Mapou et al., 1993
; Mason et al., 1998
; von Giesen et al., 2001
). As such, cognitive complaints or self-reported functional ability may not be accurate assessments of true performance. Rather, functional complaints may indicate mood disturbances, such as anhedonia, that could interfere with everyday functioning independently of functional ability.
Under-reporters constituted approximately 13% of participants who were consistent in self-reporting style. Not only is this concerning in the context of patient welfare, but also patient unawareness may be misinterpreted by the clinician as a “stable” or “improved” level of functioning. Inaccuracies in self-report highlight the importance of integrating objective laboratory based measures of functional abilities in clinical assessments of individuals with illnesses, such as HIV, that often co-occur with depression (Castellon et al., 2006
). Clinically, this is important when evaluating functional decline, as over-reliance on self-report may lead to inaccurate diagnostic conclusions.
The ability to function independently is an important consideration when determining a diagnosis of HIV-associated Neurocognitive Disorder (HAND; Antinori et al., 2007
). As outlined in the HAND nosology, in order to diagnose HIV-associated mild neurocognitive disorder, cognitive impairment must produce mild interference with daily functioning. This may be established using performance-based measures based functional measures such as those in the current study, as well as by patient self-report or observation by others. As demonstrated by this study and others, relying on self-report among depressed individuals can lead high rates of false positives.
In sum, our findings underscore the importance of considering depression and cognitive ability when assessing self-reports of functional status among individuals with HIV. More importantly, findings from our study suggest that using objective IADL measures such as the Medication Management Task may more accurately detect declines in functional ability than self-report. Just as over-reliance on subjective self-report of cognitive status can lead to diagnostic error, over-reliance on patients’ self-reported claims of functional decline, or lack thereof, should be avoided.