IS THIS ALL IN MY HEAD?
If there is one question that all physical therapists will tell you they hear over and over again from patients, this is the one.
The “this” in this question is pain.
More specifically, it usually is asked in reference to chronic pain, the kind of hurting that seems to be persisting for much longer than expected and was originally caused by some kind of injury, such as to the low back or neck, to name two of the most common areas affected in this way. People suffering from this long-term pain seem to have an innate sense that this is not normal, that the discomfort “should be gone by now,” and when it isn’t, they begin to question whether it is something they are imagining – that it’s “all in my head.”
It’s a legitimate question, and one I will try to answer to the best degree possible given the current state of scientific knowledge on the topic. The first thing we need to understand is what we mean exactly when we talk about “chronic” pain.
Experts in the field of pain differ in what they consider the necessary period of time that must pass before they apply the “chronic” label, but 12 weeks generally seems to be the average.
Why does 3 months seem to be the standard time for changing the description of pain from acute (or sub-acute) to chronic? Understanding what happens in our bodies when we are injured is crucial to appreciating why we change our terminology as time passes.
As an example, let’s look at low back pain, generally thought to be the result of some injury to the lumbar spine. This can involve the ligaments, tendons, muscles, discs, or nerves in that region, and quite often we really do not know which of those structures has been injured specifically, causing us to feel pain. (See blog entry #1) Nonetheless, if you feel significant pain after you’ve lifted something heavy, fallen, or twisted unexpectedly or excessively, almost certainly you’ve caused some disruption to some part of your spinal column.
When that happens, the nerves in the area – even if they themselves are not the main structure injured – send a signal to your brain that something’s wrong, and that signal is perceived as pain. In some sense, it’s an alarm going off telling you to stop whatever it is you’re doing that’s causing injury. (If it hurts when you do that – don’t do that!) Our body will then start the process of limiting the damage and then repairing it. We usually refer to this as the inflammatory response, which is, for the most part, a natural occurrence. The swelling and pain that often accompanies this response is designed to tell us to take it easy for a while until the injured part has healed, a process that usually takes anywhere from 2 to 8 weeks, depending on the severity of the injury.
The important thing to realize is that, without our brain, there would be no pain, sort of like there being no sound from a tree falling if no one is in the forest to hear it. So, in a real sense, pain is in your head, at least as far as perceiving it even if the problem starts elsewhere.
But what about chronic pain? Is it the same thing? The answer is – yes and no.
Chronic pain is still related to what our brain perceives, but the difference is what causes it. While acute pain is clearly generated by nerves in the area of the injury, recent research appears to indicate that chronic pain may not be. Exactly where it comes from had been a complete mystery for a long time, since we know that chronic pain persists long after the injured tissue had healed. If it wasn’t coming from the injured area, where was it coming from? This didn’t just mystify physicians and therapists; patients intuitively knew this didn’t make sense, which is why so many would ask “Is this all just in my head (i.e., imagination)?”
The answer appears to be, it is in your head, but in a very real, and not imagined, sense. Experts in the field now believe that patients who suffer from chronic pain are experiencing a malfunction of sorts in the nervous system, whereby the pain-sensing centers of the brain have created a looping playback of the original signals received from the nerves in the injured structures. While those nerves are no longer sending a message to the brain, your brain is sending the message to you that says “Ouch!”
Many people have a hard time accepting that this can be the case since, in the instance of musculoskeletal injuries such as the ones we see in the spine, movements or positioning that seemed to increase the pain in the acute stage still do likewise in the chronic condition, so it seems logical to assume there is still a problem at the original site. There is evidence, though, that this is due to a learned response in the brain that is exclusively responsible for the felt pain or at least exaggerating it. In the latter case, it is thought that the whole nervous system has become over-sensitized, so that even a little stimulation to a structure – which under normal circumstances would not even be felt – is perceived as painful.
An excellent example of this phenomenon that may help illuminate this mystery is the condition known as “phantom-limb pain,” which is a very common condition experienced by patients who have undergone a limb amputation. A large proportion of such patients will describe feeling pain in a foot or hand that no longer exists, and this has been documented for centuries. Physicians thought for years that it was generated by the nerve endings in the remaining limb stump, but have come to understand that it actually is due to the changes in the brain that occurred as a result of the pain felt in that area prior to the amputation.
Why do most people recover within a few weeks from an injury while others go on to develop this chronic pain? Well, that is still not well-understood. There is speculation that stress and anxiety play a role and there is even recent research that implicates a genetic factor. Much work in this area remains to be done before we can claim to really know the best ways to address this problem.
So why is what we do know, this new knowledge on chronic pain important? It turns out that simply understanding the mechanisms of chronic pain helps patients overcome it to some degree, if not completely.
We have known for years that exercise is probably the most effective intervention for chronic pain, but getting patients to buy into this was difficult since that exercise often increased pain and, understandably, fear that it was causing further “damage.” Understanding the true nature of this pain and accepting the premise that “hurt does not always equal harm” helps reduce that fear, which reduces anxiety, which reduces pain, which allows more exercise, which further helps reduce pain, etc. In other words, it dials back the haywire loop in the brain.
Is this approach to treating chronic pain always successful? No – and that may be due to other factors that are beyond the scope of this explanation of the causes and nature of chronic pain. But it has been shown to be effective enough of the time to warrant serious consideration by anyone suffering from this all-too-common problem. Certainly, it is a viable and preferable alternative to the over-prescription of opioid medications that are wreaking havoc throughout our country.