Effect of environment on the long-term consequences of chronic pain

Abstract

Much evidence from pain patients and animal models shows that chronic pain does not exist in a vacuum but has varied comorbidities and far-reaching consequences. Patients with long-term pain often develop anxiety and depression and can manifest changes in cognitive functioning, particularly with working memory. Longitudinal studies in rodent models also show the development of anxiety-like behavior and cognitive changes weeks to months after an injury causing long-term pain. Brain imaging studies in pain patients and rodent models find that chronic pain is associated with anatomical and functional alterations in the brain. Nevertheless, studies in humans reveal that lifestyle choices, such as the practice of meditation or yoga, can reduce pain perception and have the opposite effect on the brain as does chronic pain. In rodent models, studies show that physical activity and a socially enriched environment reduce pain behavior and normalize brain function. Together, these studies suggest that the burden of chronic pain can be reduced by nonpharmacological interventions.

Figure 1

Depiction of the adverse effects associated with chronic pain and how environmental and life-style factors alter pain and its comorbid factors. Chronic pain is associated with anxiety, depression, cognitive dysfunction and changes in the brain. Stress and negative mood can exacerbate chronic pain, whereas positive mood, cognitive-behavioral therapies, exercise, social support, and mind-body and relaxation techniques can reduce the impact of chronic pain.