Pain is largely a misunderstood construct. This is odd, as everyone has experience with pain, and it has been studied extensively. Nevertheless, it remains a mystery, even to those who believe they know it best.
What we understand as pain is not a unilateral function. There are in fact two basic and primary components to pain. The first is the obvious: the physical or “nociceptive” aspect, which involves specific and particular nerve cells that respond to specific and particular stimuli. For example, one type of receptor cell responds to pressure, another to temperature. They only respond to their own stimuli, then send a message – in a BIG hurry – from peripheral to central nervous system. The reason for this is obvious – if we put our hand in a flame and receptors that respond to temperature perceive a major problem, you want to get your hand out of the fire in a hurry. There isn’t time to go through various synapses and brain circuits via different lobes and nuclei. You need to get your hand out of the fire NOW.
However, there is another no less essential component of pain – the “emotional” or affective component. For you brain anatomy fans, it likely involves the cerebellum, the insula, and the anterior cingulate gyrus – among others. More important, however, is the role of this component of pain in survival. It is this component of pain that helps encode the experience so that we don’t stick our hand in the fire next time. Now I’m sure the anatomy fans are screaming “What about the amygdala!!!??!” Yes, our friend Amy is involved, but her role in the circuitry is not as easy to track via current imaging. So please sit back down and stop sputtering. Anyway, the importance of this cannot be overstated, as this aspect of pain is essential not only to survival but also to understanding both “chronic pain” and “psychological disorders” such as PTSD.
Considering that last sentence, what PTSD and chronic pain have in common is not what you might imagine. It is certainly NOT some inherent weakness in the organism, and if you even considered that, go back 15 spaces. I’m tempted to say just go away, but if you can stow your ignorance, you might learn something. What they have in common is quite different and separate from one to the other.
In chronic pain, the circuit that involves affective (emotional for lack of a better, more commonly understood word) pain, is active long beyond the stimulus-response of the nociceptive pain response. It is not constantly or continuously active, usually, but does not depend on an exogenous stimulus to activate. However, an exogenous or endogenous stimulus CAN activate it, for example, when someone with structural damage wakes up in the morning in considerable pain from both lack of movement or untoward movement during sleep or from the level of pain medication dropping below efficacy. Moreover, withdrawal can set it off. It is this aspect of pain that is perceived or reported as “my whole body is on fire” or “it feels like someone took a very sharp knife, held it over a flame, then stuck it in my back” or “someone took the knuckle of their middle finger and pressed it into my spine and twisted it – over and over and over.” Although this may sound like exaggeration or confabulation to the uninitiated, it is not. Absolutely not. It is as real as the pain experienced when the initial injury hit, or when one holds one’s hand over a flame. That modern medicine and psychology (and neuropsychology) do not, or perhaps cannot, understand or comprehend this is not a matter of the factual basis of the report, rather it is a matter of the deficiencies in modern medicine and psychology.
To clarify further, the role of the affective component of pain in PTSD is quite different, but no less significant. To leap forward without going through a lot of discussion and explanation, I will simply say that the expression “painful memories” is literal. Memory in individuals with PTSD activates the affective pain circuit, causing an experience of pain no less real than any of the others mentioned above. However, it may not be understood by the individual as pain, as society has so misconstrued both pain and PTSD – society including medicine and psychology.
Just as the phrase ‘painful memories’ has a folk wisdom that exceeds our current scientific wisdom, so does the following: We feel pain. It is essential to understand that to feel pain is not the same as to perceive pain. The perception of pain, when we perceive pain, is via the nociceptive network. The “feeling” of pain comes via the affective network. That is what the individual with PTSD has in common with the individual with chronic pain. They both feel pain without or beyond the perception of pain.
Until doctors understand these things, they will continue to blame their inability to treat conditions such as PTSD and chronic pain, and other notoriously difficult-to-treat disorders, on the patient. Worse, patients will be subjected to therapies that ultimately do not and cannot work.
The numbers of individuals coping with pain – chronic or postraumatic – are huge and growing rapidly. Posttraumatic stress has been vastly underestimated as has the degree of anguish involved in affective pain in both PTSD and chronic pain. Major advancements are not made by following existing pathways. Although I believe that the empirical supersedes anecdotal thought and evidence I also believe wisdom supersedes knowledge. I hope that we will be able to apply advances in brain science with sufficient compassion and empathy, and wisdom, to allow us to better understand what is involved in the development and the treatment of affective pain.