Age, Sex and Race Effects on Placebo Analgesia: Results from a Large Cohort Study in Chronic Pain and Healthy Participants

This talk will present recent results with sex, race, and age being explored in a large cross-sectional study enrolling over 800 chronic pain patients and matched controls. Colloca and her team were the first to demonstrate influences of race/ethnicity on placebo hypoalgesia. Racial effects on placebo hypoalgesia are small and negligible. AfroAmerican/Black participants have lower placebo effects which are mediated by conditioning strength. Concordance between the experimenter and participant race induced greater placebo hypoalgesia in chronic pain patients hinting to the fact that disparities and racial biases may play a role. Independently of gonadal hormone levels, women show stronger placebo effects than men. There were also statistically significant sex differences for the conditioning strength and reinforced expectations whereby reinforced expectations mediated the sex-related larger placebo effects in women. Finally, distinct adulthood ages contribute to larger placebo effects in chronic pain patients with placebo effects (unpublished data). Overall, these findings are new, informative for clinical practice and trials and new age-related research approaches.