Practical Science on Movement and Pain
Practical Science on Movement and Pain
I have recently noticed several comments on the blogosphere which compare the ideas of Dr. John Sarno to the findings of modern pain science. While there may be some superficial similarities, there are some very important differences that I would like to clarify in this post.
First, Sarno’s theories are generally considered to be untested and speculative, and are looked upon with significant skepticism by mainstream science. Sarno himself admitted that his theory is not accepted by 99.99% of the medical community. (But Andrew Weil, Mehmet Oz and Howard Stern are fans!) By contrast, the basics of pain science that I discussed in previous posts are very well accepted (despite being generally ignored), and are supported by a great amount of research and solid theory by many leading neuroscientists.
While this does not prove that Sarno is wrong about anything, it at least demonstrates that his theories are quite different from the pain science principles I have outlined in various posts on this blog. So let’s review his major claims and compare them to some of the basics of modern theories on pain.
Sarno’s theory is that a great deal of chronic pain, including most back pain, is caused by a condition he calls Tension Myositis Syndrome or TMS. The basic idea is that TMS is initiated in the brain, not the body, as a result of the brain’s psychological need to repress deep emotional issues such as anger. According to Sarno, the brain creates pain as a “distraction” to avoid dealing with troubling emotions. The brain does this by using the autonomic nervous system to restrict blood flow to certain tissues of the body, resulting in hypoxia and then pain.
Sarno treats patients by convincing them that their anger or rage or whatever emotion being repressed is the true cause of their pain and that there is no actual damage to the body parts that hurt. Patients are encouraged to return to normal activity, cease physical therapy and possibly undergo psychological therapy. According to Sarno, once the client recognizes the symptoms for what they really are, they go away.
Now let’s compare Sarno’s theory to the core claims of pain science. Modern theories of pain are well exemplified by what is now called the neuromatrix theory of pain, based on the work of Ronald Melzack and , and more recently articulated in some excellent research, articles, and books by Lorimer Moseley.
The neuromatrix theory embodies a fundamental paradigm shift from the way scientists viewed pain for hundreds of years. Beginning with René Descartes, pain was considered to be the simple consequence of the brain reading pain signals (called nociception) from the body. Under the Cartesian view, pain is an input from the body which the brain perceives passively like a paper receiving ink. Based on this idea, we would expect to see a simple one to one relationship between tissue damage and pain.
But that is not what we see. Scientists have extensively documented a huge variety of circumstances under which there is little or no correlation between tissue damage, nociceptive signaling, and pain. For example, some people suffer extreme pain with no tissue damage at all, as in the case of phantom limb pain. Some people are temporarily pain free after suffering very severe injuries in an emergency situation. Many people without back pain show herniated discs or other spinal abnormalities on MRIs. These results help prove that physical harm is neither necessary nor sufficient to cause pain.
The neuromatrix theory explains the disconnect between physical harm and pain by viewing pain as an output of the brain, not a preformed input from the body. When a body part is damaged, nerve endings send a nociceptive signal to the brain containing information about the nature of the damage. But no pain is felt until the brain interprets this information and decides that pain would be a good way to encourage action that will help protect and heal the damage. The brain considers a huge amount of factors aside from just the damage signals in making this decision, and no two brains will decide the same thing. Many different parts of the brain help process the pain response, including areas that govern emotions and past memories. The “neuromatrix” is simply the combination of brain areas that produce pain when activated. Given the complexity of the matrix and the many parts of the nervous system forming it, the processing of harm signals from the body can be upregulated, inhibited, interpreted, and misinterpreted in a stunningly wide variety of complex and interactive ways.
The neuromatrix theory explains a great deal of previously unexplainable evidence related to pain, such as why placebos work, why someone can experience pain with no tissue damage, why someone can have significant tissue damage without pain, and why pain can be significantly affected by non-nociceptive sensory information, thoughts, memories, emotions, and social interactions.
Now let’s compare the neuromatrix theory to Sarno’s theory to compare similarities and differences.
First, Sarno is correct that chronic pain often results more from processes in the brain than from any significant tissue damage in the body. He is also correct that emotions such as anger or stress can be major contributors to pain. In fact, studies have shown that job satisfaction is an excellent predictor of back pain, and that MRI results showing herniated discs or torn rotator cuffs are nowhere near as predictive of pain as you might imagine.
Despite the support that the neuromatrix theory gives to some aspects of Sarno’s claims, he does not cite to it in his writing. This should raise concern because he has written three books on pain without citing to current pain science! (I will admit that I only read the most recent book and just browsed the others.) Sarno instead spends a great deal of time discussing Freud, the ego, the superego, and other archaic metaphorical concepts. Bad sign.
I would guess that the reason Sarno ignored the science relevant to his theories is that it directly contradicts them in a fundamental way, which is this. The neuromatrix theory proposes that the purpose of pain is to encourage you to take action to prevent or heal harm to the body. TMS proposes that the purpose of chronic pain is not to protect the body, but to repress emotion. To accomplish this goal, the brain harms the body by inducing hypoxia – on purpose! Here we have two polar opposite explanations of the brain’s intentions in relation to chronic pain – one is that pain is intended to protect the body, the other that pain is the result of the brain’s attempt to harm the body. Sarno’s view seems completely counterintuitive and raises several questions from an evolutionary perspective.
Why would natural selection create people who feel back pain when they have repressed rage? One might imagine that the ability to repress anger would be useful to get along harmoniously with other tribe members. But why would back pain be the best way to go about repressing the anger? Back pain makes you irritable, disagreeable and unable to perform useful work – these are hardly qualities that will assist you in getting along with others. (But to get empathy and avoid work? Maybe.) Surely there are more effective ways to distract us from uncomfortable emotions than pain, such as compartmentalization, denial, projection, obsession, neuroses, work, etc. Why does pain help repress emotion better than these mechanisms?
And even if pain is a good way to repress emotion, is it really worth the price? Why is repressing emotion so important that we need to create disabling pain to do it? It is hard to imagine how such a function could have evolved.
Further, even assuming the brain would have some good reason to create pain in order to repress an emotion, why would damaging the body through hypoxia be the chosen mechanism? Pain science tell us that the brain is perfectly capable of creating pain without any nociceptive signaling from the body. Accordingly, it would be theoretically unnecessary for the brain to damage the body in order to cause pain. Damaging the body to cause pain is a circuitous, inefficient and costly path to accomplish a goal that seems pointless and counterproductive.
In sum, Sarno is correct that the brain and emotional stress play a big role in chronic pain, but his proposed mechanism for how this relationship works appears implausible and inconsistent with what we know about pain science and evolution.
Of course, none of this means that his treatments do not work. That is a separate question! So if Sarno’s methods work for you, that is great, congrats on your progress and keep at it. But don’t think that proves that TMS is a real disease, or that Sarno’s methods work by curing it.