Predicting chronic pain two years following a spinal cord injury: Longitudinal study on the reciprocal role of acute pain and PTSD symptoms

Objectives: To examine a) the development of PTSD symptoms and pain over five months post-spinal cord injury (SCI); b) the directional effects of PTSD symptoms and pain across five months post-SCI; and c) the prediction of chronic pain two-years post-SCI by PTSD symptoms and pain severity in the first five months post-SCI. Study Design: Two-year longitudinal study. Setting: : Individuals with an SCI admitted to the Department of Neurological Rehabilitation (N = 65). Outcome measures: : PTSD symptoms and pain were evaluated at 1.5 months (T1), three months (T2), and five months (T3) post-SCI. Chronic pain was evaluated at 24 months post-SCI (follow-up). Results: Seventy-five percent of participants reported chronic pain at follow-up. Pain severity at T1 and T2 predicted PTSD symptoms at T2 and T3, respectively. PTSD symptoms at T2 predicted pain severity at T3. Individuals with chronic pain at follow-up had reported more PTSD symptoms at T1, T2, and T3 than those without pain. A multivariate model yielded two significant indirect paths: a) PTSD symptoms at T1 predicted chronic pain severity at follow-up through PTSD symptoms at T2 and T3, and b) pain severity at T1 predicted chronic pain severity at follow-up through pain severity at T2 and T3. Conclusions: Both pain and PTSD in the acute post-SCI phase are markers for chronic pain two years later. PTSD and chronic pain exhibit a complex, reciprocal relationship across time that contributes to pain chronicity. Identifying individuals at risk and implementing interventions targeting both pain and PTSD symptoms during the acute phase may prevent their chronification.