The role of posttraumatic stress symptoms on chronic pain outcomes in chronic pain patients referred to rehabilitation

Objectives Posttraumatic stress symptoms (PTSS) are highly prevalent in chronic pain patients and may affect pain symptomatology negatively, but there is still a great need to explore exactly how this occurs. Therefore, this study investigated differences in pain intensity, pain-related disability, and psychological distress between chronic pain patients not exposed to a trauma, patients exposed to a trauma with no PTSS, and patients exposed to a trauma with PTSS. Moreover, the moderating effects of PTSS on the associations between pain intensity and pain-related disability and psychological distress were investigated. Methods In this cross-sectional cohort study, data were consecutively collected over the course of a year in patients with chronic non-malignant pain referred for multidisciplinary pain rehabilitation at a Danish university hospital pain center using questionnaires assessing pain, pain-related disability, PTSS, anxiety, and depression. Results The final sample consisted of 682 chronic pain patients, who were divided into three subgroups (no trauma, 40.6%; trauma/no PTSS, 40.5%; trauma/PTSS, 18.9%). Chronic pain patients with PTSS reported significantly higher levels of pain intensity, pain-related disability, depression, and anxiety compared to chronic pain patients without a trauma and chronic pain patients without PTSS. Moreover, PTSS significantly moderated the associations between pain intensity and pain-related psychosocial disability, depression, and anxiety. Conclusion These results highlight the importance of assessing PTSS in chronic pain patients and suggest that PTSS have a specific influence on the association between pain intensity and more psychosocial aspects of the pain condition.