Mechanisms of heightened pain-related disability in Canadian Armed Forces members and Veterans with comorbid chronic pain and PTSD

Abstract

LAY SUMMARYCanadian Armed Forces (CAF) members and Veterans with chronic pain and posttraumatic stress disorder (PTSD) symptoms were surveyed. Participants with a high number of PTSD symptoms had a higher vulnerability to becoming psychologically traumatized by their chronic pain than participants with a low number of PTSD symptoms. In turn, participants with this high vulnerability reported experiencing more disability from their chronic pain than participants with a low vulnerability. In addition, participants with a high number of PTSD symptoms tended to have many catastrophic thoughts about their pain. In turn, these participants reported experiencing more disability from their chronic pain than participants with few catastrophic thoughts about their pain. PTSD may lead servicemembers and Veterans to experience high disability from their chronic pain by increasing how traumatized they feel by their pain and by increasing the number of catastrophic thoughts they have about their pain. Targeting pain-related psychological trauma symptoms and catastrophic thoughts when treating servicemembers and Veterans with chronic pain and PTSD may be effective at reducing disability from chronic pain.Introduction: Posttraumatic stress disorder (PTSD) is highly comorbid with chronic pain in military personnel. Individuals with both conditions experience higher pain-related disability. The mechanisms contributing to increased pain-related disability in Canadian Armed Forces (CAF) members and Veterans with comorbid chronic pain and PTSD are poorly understood. Thus, this study examined the role of two potential mechanisms of comorbid PTSD and chronic pain that contribute to pain-related disability in military personnel: sensitivity to pain traumatization (i.e., the propensity of an individual to develop a traumatic stress-like reaction to pain [SPT]) and catastrophic thinking about pain. Methods: Study participants were 165 CAF members and Veterans with chronic pain. Participants completed an online survey assessing PTSD status, chronic pain status, and questionnaires assessing SPT, pain catastrophizing, and pain-related disability. A parallel multiple mediation analysis investigated whether SPT and pain catastrophizing mediated the relationship between PTSD and pain-related disability. Results: CAF members and Veterans with comorbid chronic pain and PTSD reported significantly greater pain-related disability compared to participants with chronic pain only. Both SPT and pain catastrophizing significantly mediated the relationship between PTSD and pain-related disability. Discussion: Findings suggest that PTSD may lead to greater pain-related disability in individuals with chronic pain by increasing individuals’ susceptibility to becoming traumatized by their pain and by increasing their tendency to engage in catastrophic thinking about their pain. Targeting SPT and pain catastrophizing in the treatment of patients with comorbid PTSD and chronic pain may be an effective treatment strategy for reducing pain-related disability in patients.