Limitations and Summary
Although the study provides new insights on the stress-pain interactions some reservations should be considered. First, the manipulation induced psychosocial stress that may differ from other types of stress. Additional studies are needed to allow for generalization of the results. Second, CPM was measured with two noxious contact heat stimuli. Although this paradigm was found reliable herein and by others ]25,32[, testing of additional CPM paradigms is recommended. Third, as all subjects were adult men, the results cannot be generalized to the entire population. In conclusion, this study demonstrates that acute psychosocial stress may induce opposite effects on pain modulation depending on individual stress reactivity; high stress-reactivity induces pronociception and low stressreactivity produces antinociception. The findings may have several implications. First, it is important to study stress effects not only on a group level but also considering individual differences in stress reactivity. With respect to pain management, since reduced CPM is associated with chronic pain [46,55], high stress-responders may be at higher risk for developing chronic pain. Therefore, identification of high vs. low stress-responders and closer monitoring of the former may enable individually tailored treatment with improved efficacy. In addition, interventions for stress management may improve pain modulation and reduce the risk of pain chronicity.