Unraveling the profile of cognitive deficits associated with chronic pain: a meta-analysis and cross-sectional study.

Self-reported cognitive difficulties are a common, yet underexplored, complaint of patients with chronic pain (CP). These deficits hinder daily functioning and reduce quality of life, contributing to disability. However, the extent and profile of these impairments remain unclear. Our study synthesized findings from a meta-analysis (Study 1; n = 67 studies, 6,899 patients and controls) with data from the UK Biobank (Study 2; n = 37,139 participants with CP and controls) to ascertain the magnitude and profile of cognitive deficits on performance-based measures in CP sufferers relative to healthy controls. Study 1 considered various factors, including cognitive domains, pain diagnosis and intensity, and psychological variables; Study 2 used a novel predictive model of cognitive age to evaluate cognitive deficits between different pain, neurological, and psychiatric conditions. Results from Study 1 demonstrated moderate cognitive difficulties in CP (g = -0.48 [95% CI -0.52 to -0.43], I2 = 82.03) across pain diagnoses and cognitive domains, and proportional to pain severity and psychological symptoms. Study 2 replicated these findings, though to a lesser magnitude (d = 0.04-0.30). Furthermore, participants with higher pain severity (4+ pain sites) showed an advanced cognitive age pattern. The cognitive difficulties observed among CP participants may be indicative of stress-related advanced cognitive age, resulting from persistent and uncontrollable pain. However, it is important to note that these deficits are small to moderate in severity, and, therefore, the observation of more pronounced impairment in CP warrants further clinical evaluation, particularly if their extent appears disproportionate to pain severity.