Brain correlates of psychological trauma in chronic pain: A systematic review

Exposure to traumatic events is a risk factor for the development and maintenance of chronic pain. Similar morphological and functional brain alterations, including cognitive deficits, have been reported in studies of chronic pain and trauma. However, the brain changes associated with trauma exposure in chronic pain remain poorly understood. To understand this relationship, literature searches were conducted in three electronic databases. Eligible studies were observational and included adults with chronic pain, reported changes in brain morphology or function associated with trauma exposure in childhood or adulthood. Pairs of independent reviewers screened titles/abstracts and full-texts, and extracted data. Risk of bias was assessed using the Newcastle-Ottawa Scale and certainty of evidence was assessed using GRADE. Thirteen studies were included. Exposure to childhood adversity (n = 7; very low certainty evidence) was associated with morphological and functional alterations of the anterior cingulate cortex, superior frontal gyrus, hippocampus, insula, and regions pertaining to the broader salience network. Trauma exposure in adulthood (n = 6; very low certainty evidence) was associated with morphological and functional alterations in the hippocampus, insula, anterior/middle/posterior cingulate cortex and superior temporal gyrus. Trauma-related impairments in language, memory and overall cognitive functioning were reported in individuals with chronic pain exposed to either childhood or adulthood adverse experiences. The results indicated evidence for brain alterations associated with trauma exposure in people with chronic pain. Aberrant structure and activity in the salience and default mode networks may represent markers of later development of chronic pain post-trauma, pointing to the potential use of network-focused and emotion-targeted interventions.