Elevated pain, hyperalgesia, and psychological discomfort are all concerned with Posttraumatic stress disorder (PTSD). Chronic pain (CP) and PTSD usually co-occur as a by-product of a traumatic event. For instance, almost 75% of people with PTSD report chronic pain after a motor vehicle accident (MVA).

Outlier Croatia, Netherlands, and UK (European countries) have the highest prevalence of PTSD whereas the lowest is found in Switzerland and Spain. This study was performed to examine the anti-nociceptive and pro-nociceptive pain mechanisms, pain intensity and psychological distress (depression, anxiety, pain catastrophizing, and fear of movement). The patients considered for this study were suffering from accident-related chronic spinal pain with (N=44) and without (N=64) comorbid PTSD features. Vaegter HB and his team investigated temporal summation of pain (TSP: high pain scores to ten repeated stimulations), pressure pain threshold (cPPT), tolerance (cPTT) and conditioning pain modulation (CPM: rise in cPPT during cuff pain conditioning on the contralateral leg) using the cuff algometry. Heat pain threshold (HPT) and warmth detection threshold (WDT) at hand were also examined. Questionnaires were used to determine the psychological distress, PTSD symptomatology (ICD-11) and clinical pain intensity (numerical rating scale). The potential psychological mediators in the connections between PTSD and pain (intensity and mechanisms) were revealed with the help of mediation analyses. It was found that patients with PTSD displayed escalated pain intensity, psychological distress and also reduced WDT and cPTT compared with patients without PTSD (P<0.05). There were no remarkable differences in cPPT, HPT, TSP, and CPM. The connection between PTSD and pain intensity was arbitrated by pain catastrophizing, and fear of movement refereed the association with cPTT.

Hence, the relationship between PTSD and pain intensity follows the mutual-maintenance and fear-avoidance models. For future analysis, the variations in pain intensity and mechanisms after treatment focusing the comorbid PTSD in chronic pain patients should be examined.