Chronic pain is a growing issue across the globe and has obvious impacts on quality of life including physical, psychological, and social well-being. According to Rikard et. al. (2023) in a study conducted by The Center for Disease Control (CDC), an estimated 20.9% of U.S. adults (>50 million people) reported that they experience chronic pain, and 6.9% (>17 million persons) reported that they experience high-impact chronic pain (such that results in a substantial impairment to daily activities) with a higher prevalence among non-Hispanic American Indian or Alaska Native adults, adults identifying as bisexual, and adults who were divorced or separated. Despite advances in medical research and treatment, rates have risen half a percentile since 2016. The rationale behind the lack of improvement in these statistics may be found by examining the role of brain plasticity, the impact of stress and trauma, and the complex interplay between biological and environmental factors.
Brain plasticity—the brain's ability to adapt and change in response to new experiences, including injury—plays a significant role in the development of chronic pain (Gatchel et. al., 2014). Plasticity can cause membrane excitability and synaptic efficacy, which often leads to “an enhancement in the function of neurons and circuits in nociceptive pathways” (Latremoliere & Woolf, 2009). This phenomenon is called central sensitization. One example is phantom limb syndrome, where the brain continues sending pain signals to the site of an injury that has healed, or to a site that no longer exists on the body. Another example is somatoform disorder, where the brain essentially simulates severe pain stimuli despite its physiological absence to such a degree that one is indistinguishable to the individual from the other. In many cases, however, the stress and trauma of such events can manifest true physiological reactions.
McBeth et al. (2015) suggested that chronic stress (i.e. the onset of prolonged psychosomatic symptoms and an individual's continued preoccupation with them) can lead to changes in the body’s stress response system, including increased inflammation and altered pain perception. Additionally, MacBeth et. al. (2017) demonstrated that individuals who experience high levels of chronic stress are at increased risk of developing chronic pain conditions such as fibromyalgia and chronic fatigue syndrome (CFS). However, psychosomatic pain does not have a chronological prerequisite. In some instances, such as the anecdote outlined below, it can be experienced acutely:
In 1995, the British Medical Journal published a report by Fisher et. al. (1995), detailing how a 29-year-old construction worker suffered an accident on the job which constituted a 7-inch nail pierced his boot clear through to the other side. In terrible pain, the man was rushed to the hospital, where he was sedated with several opioids on arrival. However, when his medical team removed his boot, they found that the nail had not penetrated his skin at all, but was instead stuck between two toes.
Mansour et. al. (2014) argued that the theoretical construct of non-physiological pain is “a strong departure from the traditional scientific view of pain, which has focused on encoding and representation of nociceptive signals”. Mansour et. al. (2014) believed the definition of chronic pain should be “recast within the associative learning and valuation concept, as an inability to extinguish the associated memory trace, implying that supraspinal/cortical manipulations may be a more fruitful venue for adequately modulating suffering and related behavior for chronic pain”. If the new definition were applied, the roots of pain could be traced to an array of biopsychosocial factors.
The interplay between biological, psychological, and environmental factors in relation to pain is complex and multifaceted. According to Diatchenko et al. (2019), genetic factors may predispose individuals to chronic pain, but environmental factors such as stress, trauma, and lifestyle factors can also play a role. Additionally, social and cultural factors can impact the experience of pain, with a study by Green et al. (2003) showing that individuals from certain cultural backgrounds may be more likely to experience chronic pain. Societal attitudes toward pain and pain management may also influence the development and treatment of chronic pain conditions. A culture that values stoicism and downplays the importance of pain may lead individuals to delay seeking treatment for chronic pain compared to a culture with an economy that thrives off of its members seeking treatment for chronic pain. This highlights the need for a comprehensive approach to treating chronic pain that takes into account both biological and environmental factors.
The rise of chronic pain rates is an issue that requires a nuanced understanding of the interplay between biological and environmental factors. Dr. Anna Zajacova, a professor in the Department of Sociology at the University of Western Ontario in London, Canada, suggested in a 2021 article published by Medical News Today that despite the emphasis the U.S. healthcare system places on procedures and medications, the focus for patients experiencing chronic pain “needs to shift to prevention and management, including support of self-management and interdisciplinary conservative treatment approaches”. Zajacova calls for policy directives such as “increasing funding for pain treatment, especially interdisciplinary approaches to managing pain” but, in the interim, urges clinicians to trust their ability to provide support to their patients and empathize with their lack of access to treatment. Lastly, Zajacova states that “while medicine recognizes the ‘biopsychosocial roots’ of chronic pain, clinicians are often compelled to look for an underlying, hopefully treatable, physical condition.” By acknowledging the complexity of how chronic pain develops in the brain, and how the biopsychosocial root of chronic pain can be traced back to an array of sources within an individual, care teams can begin to identify and implement the specific methods of intervention needed in comprehensive and effective treatment plans.
Diatchenko, L.; Fillingim, R.B.; Smith, S.B.; Maixner, W. (2019). The genetics of chronic pain: a review. Journal of Pain, 160(1), 537-548.
Fisher, J.P.; Hassan, D.T.; O’Connor, N.M. (1995). British Medical Journal, 310:70
Gatchel, R.J.; Peng, Y. B.; Peters, M. L.; Fuchs, P. N.; Turk, D.C. (2014). The biopsychosocial approach to chronic pain: scientific advances and future directions. Psychological Bulletin, 140 (3), 1-67.
Huzar, T. & Flynn, H. (2021). More and more US adults have chronic pain, new study shows. Medical News Today. https://www.medicalnewstoday.com
Latremoliere, A. & Woolf, C.J. (2009). Central sensitization: a generator of pain hypersensitivity by central neural plasticity. Journal of Pain, 10(9): 895-926.
Mansour, A.R.; Farmer, M.A.; Baliki, M.N.; Apkarian, A.V. (2014). Chronic pain: the role of learning and brain plasticity. Restorative Neurology and Neuroscience 32(1): 129-39.
McBeth, J.; Lacey, R.J.; Wilkie, R. (2015). The role of stress and trauma in chronic pain and illness. Advances in Psychosomatic Medicine, 34, 30-43.
McBeth, J.; Mulvey, M.R.; Macfarlane, G.J. (2017). Chronic pain: making the invisible visible. The Lancet, 389(10072), 1279-1290.
Rikard, S.M.; Strahan, A.E.; Schmit, K.M.; Guy, G.P. Jr. (2023). Chronic Pain Among Adults — United States, 2019–2021. The Morbidity and Mortality Weekly Report, 72: 379–385.