Anxiety Sensitivity Does Not Enhance Pain Signaling at the Spinal Level

Objectives: Anxiety sensitivity (AS) is the fear of anxiety-related sensations and its perceived harmful consequences. AS is associated with enhanced pain and worsened pain outcomes, suggesting it is a contributing factor in acute and chronic pain. However, the mechanisms that mediate the relationship between AS and pain are currently unknown. This study assessed the relationship between AS and 2 measures of spinal nociceptive processes (ie, nociceptive flexion reflex and temporal summation of nociceptive flexion reflex) and measures of subjective pain. This allowed us to determine whether AS engages descending cerebrospinal processes to facilitate pain signaling at spinal levels. Methods: AS was assessed in healthy men and women using the Anxiety Sensitivity Index-Revised. Then pain processing was assessed from electric pain threshold, nociceptive flexion reflex threshold, temporal summation of pain, temporal summation of nociceptive flexion reflex, and McGill Pain Questionnaire sensory and affective pain ratings. Associations among variables were assessed using Winsorized correlations (a robust and statistically powerful analytic method). Results: AS was positively associated with sensory pain ratings, affective pain ratings, and temporal summation of pain, but was unrelated to all other outcomes. Discussion: Given that AS was not significantly associated with measures of spinal nociception, these results suggest that AS may exert its influence on pain processing at the supraspinal, rather than the spinal level.