Influence of post-traumatic stress disorder on pain experience in subjects on opioid maintenance therapy

Thesis (M.A.)--Boston UniversityPost-traumatic stress disorder (PTSD) and pain often co-occur in the same subjects. Chronic pain is a common symptom in subjects with PTSD and PTSD is a risk factor for chronic pain and the related disability. PTSD is also highly prevalent in subjects with substance abuse disorders. While a number of studies have examined interactions between PTSD and chronic pain in general populations, these studies have generally used self-reported pain instead of experimental pain testing methods. To date, little is known regarding the influence of PTSD on pain experience in subjects on opioid maintenance therapy for the treatment of opioid addiction. We tested the hypothesis that PTSD is associated with altered pain experience in subjects on opioid maintenance therapy. Specifically, we examined whether subjects with PTSD would 1) have altered sensitivity (pain tolerance and temporal pain summation) to experimental pain testing and 2) self-report higher pain severity and pain interference as compared to controls. Forty-one eligible subjects were assessed in the study. All subjects were screened for PTSD using the PTSD Checklist Civilian Version (PCL-C). A PCL-C score ≥ 44 was considered as a positive PTSD diagnosis. The experimental pain testing and self-assessment of pain experience were compared between subjects with and without PTSD. Multivariate analysis was used to assess the relation between PTSD and the pain responses adjusting the covariates. Our results showed that the presence of PTSD did not alter the response to experimental pain testing but significantly increased the degree of pain interference as revealed by the subjects’ self-assessment of pain experience. These divergent results suggest that in subjects with PTSD there is a disconnection between self-reported pain experience and response to experimental pain testing with an objective stimulus. The findings discussed in this thesis are limited by small sample size. Further study with a larger sample size and broader array of pain tests is suggested