Predicting complaints of impaired cognitive functioning in patients with chronic pain.

Patients with chronic pain often complain of difficulties with cognitive functioning. Previous studies suggest that these occur with no history of head trauma or neurological disease. This study examined potential predictors of cognitive complaints in 275 consecutive patients referred to a university pain management center. Patients completed a brief set of self-report measures of problems with cognitive functioning, biographical information, pain severity, pain location, depression, anxiety, sleep quality, medication use, and litigation status during their first visit to the clinic. The most frequently reported cognitive complaints included forgetfulness (23.4%), minor accidents (23.1%), difficulty finishing tasks (20.5%), and difficulty with attention (18.7%). Fifty-four percent of patients reported at least one problem with cognitive functioning. Correlation analyses showed that using antidepressants, pain severity, pain-related anxiety, and depression were moderately associated with total cognitive complaints. Regression analyses showed that depression accounted for the largest unique proportion of variance in cognitive complaints (DeltaR2 = 29%). Given the high frequency of complaints of impaired cognitive functioning, this realm of functioning deserves routine assessment. When these complaints are encountered, a careful evaluation considering a range of neurological, social, and emotional influences is in order.