Longitudinal interactions of pain and posttraumatic stress disorder symptoms in U.S. Military service members following blast exposure

Abstract

Military personnel returning from conflicts in Iraq and Afghanistan often endorse pain and posttraumatic stress disorder (PTSD) symptoms, either separately or concurrently. Associations between pain and PTSD symptoms may be further complicated by blast exposure from explosive munitions. Although many studies have reported on the prevalence and disability associated with polytraumatic injuries following combat, less is known about symptom maintenance over time. Accordingly, this study examined longitudinal interactive models of co-occurring pain and PTSD symptoms in a sample of 209 military personnel (mean age = 27.4 years, standard deviation = 7.6) who experienced combat-related blast exposure. Autoregressive cross-lagged analysis examined longitudinal associations between self-reported pain and PTSD symptoms over a 1-year period. The best-fitting covariate model indicated that pain and PTSD were significantly associated with one another across all assessment periods, χ² (3) = 3.66, P = .30, Tucker-Lewis index = .98, comparative fit index = 1.00, root mean squared error of approximation = .03. PTSD symptoms had a particularly strong influence on subsequent pain symptoms. The relationship between pain and PTSD symptoms is related to older age, race, and traumatic brain injury characteristics. Results further the understanding of complex injuries among military personnel and highlight the need for comprehensive assessment and rehabilitation efforts addressing the interdependence of pain and co-occurring mental health conditions.

Perspective: This longitudinal study demonstrates that pain and PTSD symptoms strongly influence one another and interact across time. These findings have the potential to inform the integrative assessment and treatment of military personnel with polytrauma injuries and who are at risk for persistent deployment-related disorders.

Keywords: Chronic pain; blast injuries; longitudinal studies; military personnel; posttraumatic; stress disorders.

Figure 1. Best-fitting autoregressive cross-lagged model with covariates included

Notes: Solid lines represent significant (p< .05) standardized regression estimates. Broken lines represent paths that were included in the model but were not statistically significant. PTSD= posttraumatic stress disorder; TBI= traumatic brain injury; AA= African-American. Only the statistically significant pathways for the covariates of age, race, and TBI injury status are illustrated in this figure.