There are a significant comorbidity between PTSD and chronic pain. Thus, studies clarifying the vulnerability and protective variables and mechanisms associated with PTSD and chronic pain are needed. The aim of this study was to examine the association between trauma, resilience, PTSD symptoms, and the variables included in the fear-avoidance models (anxiety sensitivity, catastrophizing, fear-avoidance beliefs, fear of pain, pain hypervigilance) as well as pain acceptance and experiential avoidance in explaining adjustment to chronic pain (pain intensity, pain-related disability and emotional distress). Method: the sample consisted of 229 patients with chronic musculoskeletal back pain. Results: Structural Equation Modelling was used. Statistical tests indicated that the hypothesized model adequately fitted the data (RMSEA = .07; CFI = .99; NNFI = .98; TLI = .96). The χ2 test was significant (χ2 (8) = 19.25, χ2 /dl = 2.40, p = .014). The results provided support for the hypothesized model. All the standardized path coefficients were significant (p < .05). Conclusions: This study provides empirical support for the potential role of PTSD symptoms in fear-avoidance models of chronic pain, and may provide support for the diathesis-stress model of pain. It is the first comprehensive model of adjustment to pain to consider vulnerability and protective adaptation mechanisms in patients who have undergone a traumatic event. The study highlights the importance of a comprehensive framework of reference to understand the comorbidity of PTSD and chronic musculoskeletal pain, and the need to provide well-designed treatment programs for the simultaneous treatment of these conditions.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
