How Is Chronic Pain Born?
How does pain turn from acute to chronic? On the brain's 'danger mechanism,' the self-feeding 'pain cycle,' and how change becomes possible.
In previous articles we talked about what pain is, how it often exists even without a physical injury, and we debunked several common myths — among them that ongoing pain is usually unrelated to imaging findings, and isn't caused by weak muscles, bad posture, or even the change of seasons.
In this article I'll explain in more depth the process by which the brain turns pain into something ongoing (chronic).
If we've had some kind of injury, the nervous system in the injured area will usually pass information to the brain about the injury, and the brain will produce a pain experience. Over time, as the injury heals (and this is the place to say that the vast majority of injuries heal within a few weeks or a few months), the sensory information reaching the brain normalizes, and the brain lowers the pain level accordingly. But in certain cases, this process can go somewhat awry.
In a minority of cases there really can be an injury that hasn't healed within a few months. These cases are very rare, and a competent doctor will usually be able to rule them out. They include a fracture that hasn't united, chronic inflammation, a malignant tumor, or sustained pressure on nerves and blood vessels.
In the vast majority of cases where pain persists over time, the injury did heal, and the nerve signal from it to the brain returned to normal — but the brain can "fail to get the message" and keep transmitting pain. The pain is of course entirely real (it can even be stronger than "ordinary pain"). This happens when the brain (and when I say the brain I mean, of course, unconscious regions that trigger the pain experience automatically and beyond our control) keeps activating the "danger mechanism" that amplifies the pain experience. That "danger mechanism" is created in several regions of the unconscious brain (the limbic lobe, the brainstem, and more) and is tied to our beliefs, our thoughts, our emotions, our stress level, and our behavior around the pain.
- If I believe my body is "broken" or weak, if my levels of fear or frustration about the pain are very high, if I avoid any action that might worsen the pain even slightly — the "danger mechanism" can keep running, and keep the pain high.
- If the doctor told me that "my back doesn't look good on the scan" and that I'd better not run because it's dangerous for me, or if the physiotherapist said my muscles are weak and that I walk "the wrong way" — the "danger mechanism" can keep running, and keep the pain high.
- If my boss at work is getting on my nerves, if I've been through a breakup, if my son or partner is on reserve duty, if I haven't slept well for a long time (because of the pain or for any other reason) — the "danger mechanism" can keep running, and keep the pain high.
The sharp-eyed may have noticed the circular process the pain can create — the "pain cycle." In English it's called a vicious cycle, a loop that feeds itself. In this way, the pain causes us negative thoughts or emotions (fear, frustration, worry, despair…) that can make it worse. The pain can disrupt sleep and increase physiological stress in the body, which activates that "danger mechanism" and amplifies the pain. Stress hormones (cortisol) flowing through the body over time make the nerve endings more sensitive, causing them to transmit a stronger signal and amplify the pain. And round it goes.
This is how the brain sustains and reinforces the pain, even long after the injury has healed. And for this reason, so many treatments for chronic pain that focus on "fixing" the body (medication, surgery, massage, stretching, dry needling and injections, spinal manipulation) have only a small effect on chronic pain. When the tissue has already healed and the pain remains because of neural circuits that keep transmitting, a treatment focused only on the body has little chance of succeeding.
But the good news is — when treatment is aimed at the source of the problem (the pain regions in the brain), the pain can decrease and even disappear. Studies from recent years show that this is possible, even in very long-standing pain [Ashar et al. 2020, Donnino et al. 2021, Lumley et al. 2017]. And so a treatment for chronic pain developed that involves no medication, no surgery, and no invasive procedure at all. A treatment whose aim is to rewire the brain to reduce that "danger mechanism," and through it to reduce the intensity of the pain and how much it interferes. By breaking the patient's specific pain cycles, one can gradually bring about a neuroplastic change in the brain, so that just as the brain "learned" the pain from that injury, it is also able to "forget" it.
It may sound simple written this way (and it really isn't very complicated), but usually it's not easy at all. Rewiring the brain means changing, changing habits, learning. Treatment approaches for chronic pain such as Pain Reprocessing Therapy (found to be very effective in studies at reducing chronic pain) require training, experience, and a high level of skill, and there aren't yet enough therapists who know and use them.
But there's hope. In recent years a change has been taking place in the world of pain treatment; more and more therapists and patients are starting to use these methods to treat and recover, and the message is beginning to filter into the health-care systems and the wider public too. The main goal of this article series is to raise awareness of the possibility of recovering from chronic pain, and of the various treatments that can lead there.
Disclaimer: The information in this article is for general knowledge only. It is not personal medical advice and is not a substitute for it. If you have any health problem, please consult a qualified health professional to evaluate it.