Impact of Psychiatric Co-Morbidities on Anticipation and Processing of Experimental Pain

Pain is often co-morbid with depression, trauma, and anxiety. Understanding how aspects of the multidimensional pain experience are altered by the co-morbid symptoms is important for the development of effective therapeutic interventions. We conducted behavioral and neuroimaging experiments in individuals with major depression, posttraumatic stress, traumatic brain injury, and chronic pain. Several aspects of pain anticipation and processing were altered in individuals with psychopathology compared to those without. We found that individuals with major depression experience emotional allodynia, or a subjectively enhanced perception of unpleasantness in response to temperature stimuli that are not normally perceived as unpleasant. Consistent with this behavioral manifestation, we found changes in insula response during anticipation of pain and emotional allodynia. Conversely, our studies in post-traumatic stress and traumatic brain injury show disruption within pain-modulatory network connectivity, while individuals with chronic pain show abnormal brain response to pain relief anticipation. Furthermore, we found brain phenotypes of altered response and connectivity in individuals with co-morbid chronic pain and psychopathology. Results will be discussed in relation to treatment development and personalized medicine.