Objectives: Recent models of the relationship between posttraumatic stress and whiplash pain suggest that psychological stress relating to a motor vehicle crash may influence pain perception. The mechanisms of this relationship may be through more direct, psychological pathways, or through factors proposed by the fear-avoidance models of chronic pain. This study sought to investigate the relative contribution of fear-of-pain and trauma symptomatology to daily pain and time spent in an upright posture (uptime) in chronic whiplash-associated disorder (WAD).
Methods: Hourly electronic-diary reports were used to explore the within-day relationship of psychological trauma symptoms and fear-of-pain to same-hour and next-hour pain reports and next-hour uptime (measured by accelerometers) in 32 individuals with a chronic WAD. Within-person effects were analyzed for 329 diary entries using multilevel modeling with fixed slopes and random intercepts.
Results: Reports of trauma-related hyperarousal were associated with greater same-hour pain, and this relationship was mediated by fear-of-pain. Fear-of-pain and uptime were independently associated with reports of increased next-hour pain (controlling for first-order serial autocorrelation). Fear-of-pain was unrelated to next-hour uptime, but trauma-related avoidance symptoms were associated with reduced uptime. This study supports the relationship between psychological trauma responses and pain, suggesting behavioral (avoidance) pathways and effects on pain perception through fear-of-pain. These findings reinforce the need to evaluate traumatic stress as a factor in recovery from WAD.