Understanding pain, trauma and posttraumatic stress in patients with chronic pain: A translational investigation

Background. Interdisciplinary chronic pain management programmes are costly and effective for many participants. However, it remains a conundrum as to why a substantial proportion of patients do not make clinically significant improvements in mood and functioning. Aims. This programme of research takes a translational, mixed methods approach to addressing this question, triangulating a series of interconnected basic research studies with evaluation of intervention, in combination, to: (i) explore the association between posttraumatic stress in chronic pain patients and objectively assessable event characteristics (injury severity, cause of pain (trauma- or non-trauma related), time in pain (sub-acute or chronic); and aspects of subjective patient experience of pain (complete or partial memory of the event; diffuse or specific pain); (ii) investigate developmental aspects of the co-evolution of pain and distress by exploring clinically relevant posttraumatic stress between subacute and chronic pain patients; (iii) investigate the impact of trauma on injury recovery by exploring psychological sequelae of trauma-induced compared to non-trauma related pain; (iv) explore broader premorbid and acute contextual factors impacting recovery by undertaking a case analysis of patients’ view of their lives and the impact on pain self-management. Method. In a series of five studies, chronic pain participants whose pain was traumatic in origin (N=64) were compared with both a subacute traumatic pain group (N=77) and a chronic non-traumatic pain group (N=88). A qualitative study (N=10) further investigated the impact of social history on pain self-management. Results. All groups reported significant (but similar) rates of posttraumatic stress. Further, compared to the subacute group, chronic groups reported higher rates of diffuse pain, and complete memory of their pain event. Type of pain event, injury severity scores, and gender were not associated with clinically relevant posttraumatic stress in any group. In the subacute group, a significant relationship was found between distress and partial memory of the pain event. The qualitative case study found that participants’ unique histories contributed to “self-rules” that provided a premorbid lens through which their pain was interpreted, and their pain response was informed. Conclusion. Posttraumatic stress is a significant feature of chronic pain and is already evident in the subacute phase of recovery. Vulnerability to, and maintenance of, pain and traumatic distress cannot be understood purely through the lens of objective event characteristics though these are the indices routinely collected by health experts. The subjective experience of pain holds more hope for predicting psychological outcomes. Collection of this information during hospital screening may afford a means of making more judicious judgements about resource allocation, access to services, and ultimately may provide an evidence base to inform a personalized medicine approach to treatment planning