What Doesn’t Kill You: An In-depth Look At Pain
In 2011 researchers from the universities of Michigan, Colorado and Colombia performed an experiment in which they were able to demonstrate that our brain is unable to differentiate between physical and emotional pain. They put 40 individuals who had a recent breakup into a brain scanner and watched as they gazed upon a photo of his or her dumper recalling the consternation and hurt. In separate scanning sessions, the subjects had the laboratory equivalent of a hot poker held to the forearm (an 8 on a 10-point pain scale). According to Dr Edward Smith, the results were nothing short of ‘beautiful’. To appreciate the beauty of the results, we need to understand the psychological and physiological aspects of pain.
The web-page of The Stanford Pain Management Center of Anesthesia states, ‘Because perception and tolerance of pain vary widely from individual to individual, pain is difficult to define and describe.’ It is because pain is a subjective experience that it cannot be measured objectively. We can describe it, and even, in the case of chronic diseases (i.e. arthritis) be able to rate it. However, putting a number on pain defies its subjective and varying nature. How do we know that it is entirely physical and not the result of mental duress?
Pain is a universal issue that has afflicted mankind since the origin of mankind. To date, narcotics such as morphine remain the most powerful ways to combat pain. Yet, other methods such as that of placebo have also evolved. Evidence based is constantly exploring for the best management options for pain in a given condition. Necessity demands that we thus look into both the physiological and psychological aspects along with the current scientific evidence to gain insight into it.
Humans have evolved in a way to respond to pain so as to remove them from danger. It is a blessing in disguise especially when we consider people with congenital insensitivity to pain. This essay explores some of the most mysterious realms of pain; its emotional and physical components, how pain can be changed by perception and how it can arise in a ‘phantom limb’.
THE SUM OF PAIN
While pain may be evolution’s bitter fruit for humanity, there are those of us who have learnt (perhaps unconsciously) to manipulate it; people who go through emotional distress appear to find relief from self-harm. Is it merely psychological or is there a physiological explanation for this as well?
To answer this question, we look at some relevant studies such as the one mentioned above in italics. The functional MRI scanned the subjects and showed their brains responding both to emotional hurt and physical pain with increased blood flow to a wide range of common regions — a clear sign of “neural overlap” in the way we process and experience social and physical pain.
The abstract published in The Proceedings of National Academy of Science states, “They demonstrate that rejection and physical pain are similar not only in that they are both distressing—they share a common somatosensory representation as well.’
Earlier in 2009, a study published in the same journal found that sensitivity to social rejection and physical pain are linked by the same gene, OPRM-1. A similar study found that people who have a rare variation of the same gene are acutely sensitive to physical pain and to the hurt that comes from social rejection.
Now that an overlap between physical and emotional pain has been identified, it prompts us to ask if the brain cannot differentiate between the different types of pain, then does it react to the summative effect of both?
According to The Gate Control Theory of Pain (Proposed by Melzack and Wall during the early 1960s) the spinal cord contains a neurological “gate” that either blocks pain signals or allows them to continue on to the brain. Unlike an actual gate, which opens and closes to allow things to pass through, the “gate” in the spinal cord operates by differentiating between the types of fibers carrying pain signals. i.e. Pain signals traveling via small nerve fibers are allowed to pass through, while signals sent by large nerve fibers are blocked.
The neurological gate might have a role to play in creating a summative effect of physical and mental pain. We can assume that for under normal conditions, the ‘sum’ of both types of pain is a constant so that if one decreases, the other automatically increases. This can also mean that increased tolerance to emotional pain may also result in increased tolerance to physical pain.
This simple idea is actually made use of in military tactics. We have heard the phrase, “What doesn’t kill you only makes you stronger’. Simply, put the more pain one can endure the ‘stronger’ he/she is. Beginners in the military service are first taught to conquer their fears. As fear is a form of emotional pain, it turns out that it is the fear itself that needs to be overcome.
However, this hypothesis may only hold true for the first few instances of self-harm or military training. Gradually the body develops a tolerance to pain thanks to the analgesic effect of endorphins that are released via a negative feedback mechanism to counter the pain stimulus.
PAIN AND PERCEPTION
The effects of placebo were discovered and gained recognition during the World War 2. Dr Henry Breecher, a Harvard anesthesiologist was tending to wounded soldiers. His scientific mind observed and calculated (according to his peacetime experiences) the severity of pain that the soldiers must be going through. He then compared the reaction of the soldiers towards trauma patients when he returned to practicing in the US. Astonishingly, the soldiers often claimed to feel far less pain than civilians (with the same wound) did.
Dr Howard Brody, in his book “The Placebo Response” succinctly summarizes and explains Breeche’s paradox: “While the tissue damage to the soldier and the civilian might have been identical, the meaning of the pain in the two situations were completely different. Pain for the civilian was an unmitigated disaster; it meant an inability to go about one’s daily occupation. To the soldiers it meant, first, that they had not been killed and second, that they were at-least temporarily relieved of the threat of death on the front-lines.’
Expectancy, conditioning and meaning are the basic pillars of placebo. Pain holds different meaning for different people. To some, it is actually a welcome relief despite the obvious physical duress it brings. In the light of that, the mind at-least is healed and the body seems to follow.
THE PHANTOMS LIMB
It has been described as ‘excruciating’ and ‘almost impossible to treat’. The word ‘phantom’ is exactly befitting for the source; it is a pain that is experienced in people with amputated limbs who report to feel sensation from the same area as if the limb is still there. Surgical procedures are of limited use. Like a phantoms, the pain does not die. It may disappear for a few months…always to return.
As for the neurological basis of it, the most popular theory has been put forward by Vilayanur Ramahandur, a neuroscientist who proposed that phantom limb sensations could be due to this reorganization in the somatosensory cortex, which receives input from the limbs and body. In an article published in The Journal of Neuroscience in 2001, the reorganization of motor and somaosensory cortex in upper extremity amputees with phantoms limb pain was investigated. According to it, “These results show enhanced plasticity in both the motor and somatosensory domains in amputees with phantom limb pain.”
PAINLESS BUT HOPEFUL
The above subtitle is the name of a camp founded by John and Tara Blocker whose daughter, Ashlyn suffers from congenital insensitivity to pain. A lot of people may scoff at the notion of such a camp…after all, isn’t the inability to feel pain a good thing? Why are the sufferers cast of as victims?
Because the disorder does victimize the sufferer. Ashlyn, as a baby hardly ever cried. Her parents were thrilled. She seemed to almost purr with contentment. But then something’s started to happen. Her parents noticed that she hardly ever cried, not even when she got hurt. A trip to a doctor’s office once revealed a scratched cornea….as a baby, Ashlyn did not even whimper as the eye-drops were applied to her eyes.
The mother of Gabby Gingras, who suffers from the same disorder said, “Pain teaches. Pain protects. Pain can save you from a lot of bad things in your life”.
For most of us, as humans, pain is inevitable. The slight pin prick, the hard fall to the ground, the blow to the shoulder…it serves as a warning to stay away from what the brain perceives as a dangerous stimulus. Pain is so simple, yet so complex. Its the result of the complicated bundle of nerves relaying messages to our mind, the soul of our existence. It arises in so many different forms. It has the potential to damage both our soul and our body. It can be healed by powerful narcotics or simply by perception. It can arise in places you least expect it, a source that no longer exists such as a phantom limb. Wherever it comes from it is a sign that somewhere in our body, something is wrong.
About the author: Butool Hisam is a first year medical student from Dow Medical College. She holds interest in medical research and contributes as an author at a medical blog named, Medicalopedia. She can be reached at: [email protected]
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