Combat exposure is associated with cortical thickness in Veterans with a history of chronic pain

• Groups were matched for Age and PTSD severity.
• No thickness difference between Veterans with and without Chronic Pain.
• Negative association between combat exposure and cortical thickness in Chronic Pain.
• Groups did not differ in depression, anxiety, stress, number of TBIs or age.

Chronic Pain (CP) has been associated with changes in gray matter integrity in the cingulate and insular cortex. However, these changes have not been studied in Veterans, despite high prevalence rates of CP and interactions with combat-derived disorders. In the current study, 54 Veterans with a history of CP and 103 Veterans without CP were recruited from the Translational Research Center for Traumatic Brain Injury and Stress Disorders (TRACTS). Cortical thickness from structural MRI scans was determined using the FreeSurfer software package. Results showed that Veterans with CP showed a negative association between cortical thickness and levels of combat exposure in the left inferior frontal gyrus and superior parietal cortex, as well as the right rostral middle frontal gyrus, precentral and postcentral gyri and the superior temporal cortex. These findings suggest that CP may alter the relationship between cortical thickness and exposure to the stress of combat.