Bidirectionality of Pain Interference and PTSD Symptoms in Military Veterans: Does Injury Status Moderate Effects?

Objective. Pain and post-traumatic stress disorder (PTSD) symptoms are strongly correlated in veteran populations. Arguments for which one condition predicts or worsens the other condition have gone in both directions. However, research addressing this issue has been primarily limited to cross-sectional studies rather than examinations of a potential bidirectional relationship between pain interference and PTSD symptoms over time. In addition, no studies have examined deployment injury status as potentially moderating this bidirectional effect in veterans. To address these gaps in the literature, the present longitudinal study examined whether there is a bidirectional relationship between pain interference and PTSD symptoms in a sample of male and female veterans returning from Operation Iraqi Freedom, Operation Enduring Freedom, or Operation New Dawn (N = 729) and whether deployment injury status moderates this relationship. Methods. Participants completed phone interviews regarding pain interference and PTSD symptoms at three time points, each three months apart. Results. Pain interference at Time 1 predicted worse PTSD symptoms at Time 2 for the subset of veterans who sustained injuries during deployment (n = 381) but not for veterans with pain interference who did not sustain injuries (n = 338). From Time 1 to Time 3, elevations in PTSD symptoms were mediated by pain interference for injured veterans; in contrast, PTSD symptoms did not appear to drive changes in pain interference in either group. Conclusions. These results indicate that physical symptom management should be a crucial target of psychological intervention for returning veterans with PTSD symptoms and deployment-related injuries.