Higher Dispositional Optimism Predicts Lower Pain Reduction During Conditioned Pain Modulation.

Optimism is associated with lower pain sensitivity, positive adjustment to chronic pain, and greater reduction of pain thresholds in a conditioned pain modulation (CPM) paradigm. We hypothesized that participants with higher levels of optimism would experience greater inhibition of suprathreshold pain during CPM. Seventy-seven healthy adults completed a test of optimism, the Life Orientation Test-Revised, as well as measures of depression, pain catastrophizing, and neuroticism. Participants also underwent psychophysical tests of heat pain tolerance, heat pain threshold, and CPM. CPM magnitude was calculated as the change in heat pain ratings when applied alone and simultaneously with painful pressure. Greater optimism was significantly correlated with reduced CPM magnitude (P = .013). Regression analysis was performed using optimism as a predictor of CPM magnitude while controlling for pain catastrophizing, neuroticism, depression, and age. The overall model was significant (P = .003). Significant positive coefficients were found for depression (P = .014) and optimism (P < .001) scores. These results suggest that greater optimism predicts less inhibition of suprathreshold pain, the opposite of our hypothesis. This unexpected finding may be due to factors such as perceived stress and coping differences, and suggests that modulation of threshold-level and suprathreshold pain involves different underlying mechanisms. PERSPECTIVE: This article reports that greater optimism predicts less inhibition of suprathreshold pain, in contrast with previous work showing that optimism correlates positively with pain threshold reductions. These findings suggest that the association between optimism and the function of endogenous pain modulatory systems is complex and differs for threshold-level and suprathreshold pain.