Perceived versus actual cognitive impairment in a chronic non-malignant pain sample: examining conditional effects

Numerous studies indicate discrepancies between reports of subjective cognitive impairment and objective performance on standardized measures of attention, memory, and executive function. The discrepancy is attributed to a moderating effect of depression in chronic pain patients (CPPs) with rheumatoid arthritis and lupus. We intended to clarify the relationship between perceived and actual cognitive impairment in a sample of patients with chronic non-malignant, nociceptive pain. Study approved by UAB IRB for Human Use and included individuals with unmedicated, moderate intensity pain (n=29) and healthy controls (n=30). Participants completed: a) brief neuropsychological testing, b) Cognitive Failures Questionnaire (CFQ), which assesses self-perceived cognitive deficits, and c) Center for Epidemiological Studies–Depression Scale. Conditional Process Analysis was used to determine moderating effects of depression and pain on the relationship between perceived cognitive failures and a global score on the neuropsychological measures. A significant multiple moderator model emerged, ΔR2=.06, F(1,50)=5.21, p<.05. Post-hoc analyses indicated that chronic pain was a significant moderator of the subjective-objective relationship over and above effects of demographic factors, R2=.44, F(6,22)=2.89, p<.05. The interaction between depression and subjective cognitive complaints explained a significant portion of the variability in actual performance (ΔR2=.14). In other words, actual cognitive impairment in non-medicated CPPs was predicted by depression and higher subjective impairment, as well as the interaction between predictors. We underscore the importance of assessing depression in CPPs, with impact of mood not only on pain-related outcomes, but also on perceptions of and actual neuropsychological functioning (even in the absence of pain medications). We will discuss possible pathways of this relationship, including constructs such as negativity bias, negative self-evaluation, and hypervigilance, and the impact of depression itself on cognition. Funded by an investigator-initiated grant from Cephalon Pharmaceuticals.