Imagine you sign up to a university experiment and are subjected to the next two protocols:
After you tried both, the researcher asks you to repeat one of the two, at your choice. Which one would you chose?
If you are anything like the participants from the original 1993 experience, there is a 69% chance that you would choose the second option (after which you would be informed that there is no need to actually repeat it).
This ingenious experiment tells us much about how people experience and judge pain. Far from being an objective metric, our perception of pain seems to be based on peaks of intensity and last-minute changes. In the scenario of the experiment, this meant that people chose a more prejudicial option. In the real world, this means people might often fail to seek the most effective treatments for their pain.
Pain is a complex conscious experience that integrates raw nociceptive, somatosensory, visual and auditive information, together with the colouring of our emotional state, memories and focus of attention. It follows more automatic actions such as the knee jerk reflex that aim to avoid immediate tissue damage, and over which we have no control.
Its roles are twofold:
Despite being crucial for our well-being in the short term, pain can become extremely problematic when it persists beyond the point of intervention. When there is no reason for the pain to exist, it ceases to be a helpful signal and instead becomes a severe hindrance to general health and quality of life.
Chronic pain is learned pain. One of the most revealing findings in recent pain research is the fact that chronic pain leads to large brain reorganization. Studies have shown that persistent pain is associated with a sensitization of the neural networks that process pain and a concomitant disinhibition of surrounding networks.
Both processes impair the precision of pain processing. More specifically, they help explaining some of the oddest characteristics of chronic pain, such as its ability to spread, to move from limb to limb and swap sides of the body altogether, or how simply imagining to be touching a sore limb is sometimes enough to produce pain and even swelling. In more extreme cases, pain can arise from apparently nowhere, as is the case with fibromyalgia.
Research on chronic pain has gathered consistent evidence that brain activation reflects the subjective intensity and location of pain more closely than the objective source of tissue damage or its expected intensity. Many practitioners defend that as the dissociation between pain perception and real tissue damage increases, psychological and brain neuronal treatments become prioritary.
Who Suffers From Chronic Pain?
Although it is difficult to estimate precisely, we know that chronic pain affects a large portion of the population. In Australia, conservative estimates point to a prevalence in 20% of young adults and in 30% of elderly. More surprising maybe is the fact that chronic pain is very common among young people. A large study with Dutch children and adolescents revealed that about a quarter of those surveyed had experienced chronic pain for the last three months.
Source: Mindell (2012)
As expected, older demographics show a higher prevalence of chronic pain. However, surprisingly, the affliction can also affect the young.
Of great concern is the disregard by many health practitioners towards chronic pain. A recent study of nearly a thousand adult hospitalised patients revealed that a third were being undertreated for pain. Of these, an alarming 67.5% were reporting severe pain experiences (7 on a 0-10 scale). Further analysis revealed that non-whites, the elderly, and women had significantly higher pain ratings and worse pain management evaluations. In an aggressive stance, the authors defended that pain mismanagement should be conceived as a medical error. A notion that has been defended by many others:
“A far more plausible explanation for the failure to see decreases in pain intensity ratings over time is that the treatment of pain in the hospital settings remains inadequate and ineffective.” - Gordon and collaborators., in a review of 10 years of pain research
The fact that chronic pain is mapped onto higher order cortical networks means that it is subject to the influence of many extraneous factors. Among some of the most well-studied factors are practice of exercise, diet, sleep, psychopathology, emotional regulation, social support, self-efficacy, motivation, and perceived stress.
This is nowhere more evident than in those cases where chronic pain is accompanied by major depression. For the surprise of many, neuroimaging research has started to uncover a pervasive commonality in the brain areas, neural circuits and neurotransmitters that are affected by both conditions. While researchers are still at a guess on why this happens, it is increasingly clear that effective chronic pain treatments cannot ignore the general brain and mental health of the patients.
Source: Fricton et al., al..(2015)
If this plasticity means that treating chronic pain is not as simple as prescribing an analgesic, it also suggests a room for less conventional interventions. We will briefly review a few techniques of behavior change, cognitive reappraisal, and psychoeducation.
Behavioral therapies aim at decreasing pain-signaling behaviors (such as groans, body posture, requests for assistance, or activity refusals) while increasing healthier behaviors at work, leisure time, and when with family. Other typical goals of these interventions are the reduction of medication (when appropriate) and altering the role of close ones from solicitous to distractful or even ignorant.
Behavioral therapies are frequently coupled with cognitive techniques aiming at reducing the perception of pain and changing maladaptive thoughts and attitudes. These include reducing feelings of helplessness and building a sense of control over pain, as well as learning pain coping strategies like diversion of attention, relaxation imagery, and cognitive reappraisal. An example of instructions given to participants in a successful cognitive reappraisal experiment is shown below:
“Try to imagine as hard as you can that the thermal stimulations are less painful than they are. Focus on the part of the sensation that is pleasantly warm, like a blanket on a cold day. You can use your mind to turn down the dial of your pain sensation, much like turning down the volume dial on a stereo. As you feel the stimulation rise, let it numb your arm, so any pain you feel simply fades away. Imagine your skin is very cool, from being outside, and think of how good the stimulation feels as it warms you up.”
Besides cognitive and behavioral interventions, studies have shown that simply educating about the nature of pain can be helpful. This practice, known as psychoeducation, aims at promoting positive changes in pain-related knowledge, feels of despair and hopelessness, and compliance with non-conventional forms of rehabilitation.
An emphasis of psychoeducation is given to explain that despite being common, chronic pain should not be perceived as a normal or inevitable burden. One of the most surprising results from those studies that found a wide prevalence of poor pain management among hospitalized patients was that they felt that their doctors had done the best of their abilities. This was certainly not the case, at least for the majority of doctors. Such a wrong perception creates a justification for inaction among professionals, which is worrisome because chronic pain tends to become more difficult to manage with time. It is for a reason that the pain ruler ranges from 0 to 10, and a good pain management ensures this is kept true whenever possible.
Ricardo Oliveira is a neuroscientist passionate about research and science divulgation, based in Portugal.
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