Delay and Effort-Based Discounting, and the Role of Bodily Awareness, In People Experiencing Long-Term Pain: A Cross-Sectional Study

The Relationship Between Pain and Interoception: A Systematic Review and Meta-Analysis

Interoception refers to the ability to sense internal bodily sensations. Research suggests that dysfunctions in interoception may be implicated in the transition to chronic pain, however, little work has examined interoceptive ability in pain states. Therefore, this systematic review aimed to assess whether interoception is altered in individuals experiencing pain. Following a systematic search of 4 electronic databases from inception to February 2023, 28 studies were included. Outcomes of interoceptive accuracy, interoceptive sensibility, and interoceptive awareness were meta-analysed. The risk of bias was assessed, and the certainty of the evidence was evaluated. Meta-analyses indicated that those with chronic pain display reduced interoceptive accuracy and increased interoceptive sensibility. Subgroup analyses indicated that the change in interoceptive sensibility is dependent on the measure used, with those with chronic pain scoring higher on measures focusing on attention to bodily sensations, while also scoring lower on emotional reactivity. No difference in interoceptive awareness was observed between individuals with chronic pain and pain-free controls. Only one study was found that measured interoception in those experiencing acute pain, while another study recruited those experiencing recurrent pain. These findings suggest that while those with chronic pain self-report as more interoceptively aware, they are less accurate at detecting internal bodily signals. Further research investigating domains of interoception in those experiencing acute and recurrent pain is needed. Data should be interpreted with caution as the certainty of evidence was very low for all completed analyses. This review was registered on the PROSPERO International Prospective Register of Systematic Reviews (Registration ID = CRD42022318843). PERSPECTIVE: This review considered the relationship between interoception and pain and found that an individual's ability to accurately sense internal signals is decreased in those with chronic pain, despite them reporting being more aware of internal sensations. However, there remains little research examining interoception in non-chronic pain states.

The role of chronic pain and pain anxiety in delay discounting of pain and monetary losses

Pain may alter intertemporal decisions by modifying the value of pain-related outcomes. For example, a person with chronic back pain may be faced with two choices: undergo surgery that could provide long-term relief but would involve additional short-term pain and discomfort during recovery; or continue living with the chronic pain and avoid the surgery, thus leading to overall deteriorated health. Such choices are well captured by delay discounting, which is defined as the decline in the subjective value of an outcome as the delay of its receipt increases. We investigated general pain anxiety and delay discounting of monetary losses and pain in 255 individuals with and without chronic pain. We found that people with chronic pain tend to discount the value of pain outcomes more than those without chronic pain, suggesting that chronic pain may contribute to impulsivity in decision-making related to pain. Moreover, the effect of chronic pain on delay discounting was mediated through general pain anxiety. This result, however, should be taken with caution, because the effect sizes were small, and the path model was underpowered. In conclusion, people with chronic pain might be more likely to prioritize avoiding immediate discomfort and may undervalue the potential long-term benefits of actions that could alleviate their pain in the future.