Scientists recognize this cycle of behavior, too, and have begun asking why. The answer may lie in the brain’s chemistry.
As reported in Science, researchers conducted a series of experiments that show mice in chronic pain are less motivated than their pain-free peers to seek food, even after the pain is relieved with medication.1
These experiments accounted for how pain might affect appetite and mobility. So what was the difference between the healthy mice and the mice in chronic pain?
Researchers studied the brains in both groups of mice. Specifically, they looked at a part of the brain called the nucleus accumbens, which influences motivation and behavior, prodding us to seek out or avoid certain stimuli. The nucleus accumbens were different in the two groups of mice, and that difference was attributed to a neuropeptide called galanin. (Neuropeptides are molecules that transmit information between the brain’s neurons, or nerve cells. A more commonly known neuropeptide is endorphin.)
For the mice in chronic pain, galanin suppressed pathways of activity in the nucleus accumbens. This suppression likely sapped the mice of their motivation to work for food. Moreover, this suppression didn’t go away; the affects on the brain endured even when the chronic pain disappeared.
Of course, scientists are not ready to generalize these findings to humans, and more research is needed. The causes of fatigue, depression, and emotional distress caused by chronic pain are complicated and intertwined.
However, this study brings hope that we may some day be able to alleviate some symptoms of fatigue by adjusting the chemical reactions that cause chronic pain to sap motivation.
In addition, there are some self-care and lifestyle changes you can make to help combat the fatigue that often accompanies chronic pain:
- Coping with RA Fatigue Using Therapy and Emotional Support
- Managing RA Fatigue Through Diet and Exercise
- Coping with RA Fatigue by Prioritizing and Simplifying Tasks
- Schwartz N, Temkin P, Jurado S, Lim BK, Heifets BD, Polepalli JS, Malenka RC. Chronic pain. Decreased motivation during chronic pain requires long-term depression in the nucleus accumbens. Science. 2014 Aug 1;345(6196):535-42. doi: 10.1126/science.1253994. PubMed PMID: 25082697.