For chronic pain sufferers, the daily frustrations of a condition that can impair mobility, make holding down a full-time job impossible, and draw scorn from others often leads to other psychiatric conditions. Depression, anxiety disorders, and sleep disturbances are common among patients with chronic pain, but the tension caused by external stressors may not be the only factor contributing to coexisting disorders in chronic pain sufferers. In addition to the constant stress of coping with a painful and debilitating condition, chronic pain may actually alter the brain’s neural circuitry, potentially increasing an individual's vulnerability to other psychiatric conditions.

In 2008, researchers used fMRI scans to examine the neural activity of 30 test subjects, half of whom had chronic back pain, at baseline and while performing a simple task. They reported their findings in The Journal of Neuroscience, explaining there that while task accuracy did not differ among the subjects, patterns in brain activity did. As part of what has been termed the brain’s “default mode network,” some areas of the brain become active when the brain is mostly idle, taking over for other areas that have deactivated. In healthy control subjects asked to perform an easy task, brain regions that compose the default mode network deactivated, while other areas of the brain became active. In chronic pain sufferers, however, one part of the default mode network did not deactivate, an indication that the constant perception of pain could cause disruptions in the default mode network. These disruptions can have harmful consequences for the brain, as heightened activity in areas that should be deactivated may lead to changes in neural connections or cause neurons to die.

These changes in the how the default mode network functions could have lasting consequences, and because this overly active region of the brain, the medial prefrontal cortex, is involved in emotions, chronic pain may affect the brain's ability to process information not related to pain. For chronic pain sufferers, these disruptions in the interconnected actions of the brain may contribute to the cognitive and behavioral symptoms associated with chronic pain, influencing, for example, their moods or their ability to make decisions.

The stress and frustration of a chronic and potentially-disabling condition puts individuals at risk for depression, anxiety, and other psychiatric disorders, but chronic pain sufferers should also realize that their condition may cause biological changes in the brain that could also increase their risk. These changes may increase over time, and early treatment addressing behavioral and cognitive symptoms as well as pain management may be beneficial for anyone grappling with chronic pain.