Many adults with temporal lobe epilepsy (TLE) are at high risk for cognitive deficits and often report subjective cognitive impairment; however, prior studies have shown a discrepancy between these subjective complaints and objective cognitive performance on neuropsychological measures. Mood disorders and symptoms of anxiety and depression are also common in TLE and have been linked to greater self-reported cognitive difficulties. To further understand these relationships, the current study sought to determine if symptoms of depression and anxiety mediate or moderate the relationship between subjective cognitive impairment and objective cognitive performance in adults with TLE.

Participants were 345 adults (mean age=40.7; 55% female) with pharmacoresistant TLE who completed self-report screening measures of depression, anxiety, and subjective cognitive function along with objective measures of memory and language as part of a comprehensive clinical neuropsychological evaluation. A series of linear regression analyses and bootstrapping methods were used to examine the potential mediating and moderating effects of mood on the relationship between subjective and objective cognitive function after adjusting for relevant covariates.

Consistent with existing literature, self-reported depression and anxiety symptoms were significantly correlated with subjective cognitive difficulties across all scales (all p<.001). Subjective cognitive impairment was also significantly correlated with objective memory performance on neuropsychological measures, albeit with small effect sizes (estimate range .04-.20), but unrelated to objective naming performance. Contrary to our hypothesis, depression and anxiety did not mediate or moderate the relationship between subjective complaints and objective cognitive performance.

While symptoms of depression and anxiety were independently associated with both subjective and objective cognitive ability in this cohort of adults with TLE, this study suggests that mood symptoms do not fully explain the relationship between subjective and objective cognitive function, likely reflecting the complex and multifactorial relationships among these variables. Nevertheless, our results highlight the importance of screening for depression and anxiety symptoms and assessing patient’s subjective cognitive complaints as part of a neuropsychological evaluation as each of these factors tap into a different aspect of the patient functioning. In addition, self-ratings of cognitive ability and objective measurement of cognition, while related, measure unique constructs, both of which should be assessed and considered in the evaluation of patients with epilepsy.