The Biopsychosocial Influences of Chronic Pain on Brain Changes

By Caitlin Donovan, DC

“Biopsychosocial” is a term that has been used in the medical field in association with chronic pain presentations (Jacob, 2003). Chronic pain patients are often seen by various doctors and when treatments are ineffective, the patient is categorized as having biopsychosocial influences on pain. “Bio” refers to the physical aspects of pain such as disc herniation, joint dysfunction, and muscular disturbances. “Psycho” refers to the psychological factors of the patient. Is the patient depressed or do they have any catastrophizing tendencies? “Social” may be in relation to work stability, familial relationships, and social interactions. All three aspects combined demonstrate a wide variety of information for the patient’s brain to process their pain. Through research and advancing technology, the word biopsychosocial is losing its notoriety. Today research is showing a stronger relationship of biopsychosocial aspects having neurological changes with chronic pain.

Nociceptive pain, neuropathic pain, and central sensitization are musculoskeletal conditions occurring commonly with chronic pain patients (Smart, Blake, Staines, Doody 2011). Nociceptors are pain receptors that detect afferent stimuli in the peripheral and central nervous system. These stimuli can be chemical, mechanical, or thermal stimulations that warn your body of danger. Your body’s normal response when touching a hot stove is to quickly retract your hand from the stove, a subconscious process protecting you from harm. Neuropathic pain is present with damage to the somatosensory nervous system, commonly presenting with dermatomal pain patterns. It can present similarly to nociceptive pain, but has the characteristic of radiating pain or a referral pattern. Central sensitization occurs when pain is out of proportion to the physical damage obtained. Although all three pain processes have similarities, they can be differentiated and identified with proper screening as developed by Smart et al. Identifying chronic pain and specific pain patterns is crucial in the first step of discovering biopsychosocial influences because correct diagnosis can lead to better treatment.

Nociceptive pain changes the peripheral and central nervous system, as stated above, which alters many circuits and pathways controlling various functions, including motor control. A nociception-motor interaction is identified in chronic pain patients (Nijs, Daenen, Cras, Struyf, Roussel, Oostendorp, 2012). “[T]he autonomic nervous system responds to chronic nociception with amplification of tonic sympathetic activity. Not only [are] motor and sympathetic output pathways affected by chronic nociceptive input but afferent pathways”. This demonstrates that not only are chronic pain patients suffering from pain, but they are now limited in performing every day activities. These body image changes from nociceptive pain and central sensitization result in movement abnormalities altering lifestyles of chronic pain patients.

After defining nociception and learning there are physical changes associated with chronic pain, we can look at the effect of chronic pain on the brain. Technology is developing and changing rapidly in today’s society. One tool called a functional Magnetic Resonance Imaging (fMRI) has been used in proving chronic pain changes the central nervous system (Borsook, Bercerra, 2006). It was noted chronic pain patients have “significantly greater frontal lobe activation” (Borsook, 2006). Neuronal loss is also found with chronic pain, specifically in the thalamus and lateral prefrontal cortex. Changes in the non-sensory pathways may prove psychosocial influences and changes in the brain. Depression, anxiety, and lack of motivation were related to changes in the nucleus accumbens, amygdala, hippocampus, prefrontal cortex, and anterior cingulate cortex. Further research is needed in the investigation of chronic pain and brain changes but initial steps have been made. Another study using fMRI looked specifically at back pain and found a transition from acute to chronic pain was marked by emotional involvement in the brain (Hashmi, Baliki, Huang, Baria, Torbey, Hermann, Schnitzer, Apkarian, 2013). Using technology as such helps us connect patient symptoms to physical changes which can lead to development of treatment protocols.

Chronic pain patients suffer both emotionally and physically with their symptoms. The biopsychosocial role in this research proves the multifactorial approach that must be taken when treating this population. All aspects must be considered and the patient as a whole treated. Further research in this area can only better the patient-doctor relationship with each individual.

References

1. Borsook D, Becerra LR. Breaking down the barriers: fMRI applications in pain, analgesia and analgesics. Molecular Pain. 2006;2:30. doi:10.1186/1744-8069-2-30.

2. Hashmi, J. A., M. N. Baliki, L. Huang, A. T. Baria, S. Torbey, K. M. Hermann, T. J. Schnitzer, and A. V. Apkarian. "Shape Shifting Pain: Chronification of Back Pain Shifts Brain Representation from Nociceptive to Emotional Circuits." Brain 136.9 (2013): 2751-768. Web.

3. Jacob, Gary, DC. "Biopsychosocial Perspective on Low Back Pain: Patient Provider Communications." J Minim Invasive Spinal Tech 3.Spring (2003): 27-35.

4. Nijs, Jo, Liesbeth Daenen, Patrick Cras, Filip Struyf, Nathalie Roussel, and Rob A.b. Oostendorp. "Nociception Affects Motor Output." The Clinical Journal of Pain 28.2 (2012): 175-81.

5. Smart, Keith M., Catherine Blake, Anthony Staines, and Catherine Doody. "The Discriminative Validity of “Nociceptive,” “Peripheral Neuropathic,” and “Central Sensitization” as Mechanisms-based Classifications of Musculoskeletal Pain." The Clinical Journal of Pain 27.8 (2011): 655-63.