Can chronic pain be a “learned response” to things that shouldn’t hurt? It’s an interesting idea, with obviously optimistic implications, because what is learned might also be un-learned. We do not know if pain actually ever works this way. It is a hypothesis: maybe some pain works this way. It’s an interesting idea that it’s worth discussing and exploring regardless of whether it is true.
If it's true, if pain can be learned, it offers the hope of a bit of a brain hack, a clever and surprising solution around one of the hardest problems there is. If.
The goal of this article is evaluate the hypothesis — not promote it, or to deny or overshadow many important and valid medical causes of pain. Most pain probably has a pathological origin. I think there are a surprising number of legitimate, hard-to-diagnose conditions that cause pain, and far too many clinicians shamefully and incompetently restort to dismissive pseudo-diagnoses of psychosomatic pain, anxiety, and depression — especially in women. I do not want this article to contribute to that problem, so I am stating as loudly and clearly as possible that this is just an open-minded exploration of a interesting, hopeful possibility.
What is a “conditioned behaviour”?
Conditioned behaviour refers to the well-understood psychological phenomenon of classical conditioning. A classically conditioned response is a business-as-usual response to something that wouldn’t normally call for it. If we hear a bell every time we eat a cookie, soon our brains think bell equals cookie, and soon enough we start to respond to the bell exactly as if a cookie is surely coming: happiness, salivation! It’s cookie time! New signal, same old behaviour.
We can be conditioned to link almost any stimulus with almost any response. There are many fascinating examples in the history of psychology. It’s a potent and cool phenomenon, a cousin to placebo weirdness.
A particularly relevant example is that anxiety can be a conditioned response, and it’s a short hop from anxiety to psychosomatic symptoms, which can include pain. This is a key point in the case for the basic plausibility of chronic pain as a conditioned response.
Sensation versus perception
Chronic pain is notoriously a different beast than acute pain, and it’s clear that we still have a lot to learn about how it works — enough that there’s probably still room for a major insight like “it might be a conditioned response.” While it remains speculative and debatable, there is plenty of directly relevant evidence,12 and it’s generally plausible based on what we know about chronic pain.
Pain is an experience made from a fairly predictable sensation that has to pass through the complex filter of perception, countless contextual factors that “tune” the pain, dampening or amplifying it, or changing its quality. Acute pain is usually almost pure sensation, with only a little perceptual modulation — stepping on a piece of lego causes strong pain for basically everyone. But even with acute pain, there are examples of perception overriding sensation to a surprising degree.
And with chronic pain? The big story of pain science over the last few decades is that perception is a big factor in chronic pain. The longer it lasts, the more likely pain is to get louder and stranger.
Pain as a conditioned behaviour is a plausible mechanism for how that works: that we can learn to perceive pain even where there is little or no sensation left to base it on. If pain can be learned, it’s mainly perception we’re learning — but that can be very powerful, and we know that it can probably defy sensation.
There are three main types of pain. There is still a lot of room for speculation & debate about the nature of the “other” category. If pain can be a conditioned behaviour, it’s part of that “other” circle.
Some “simple” psychosomatic pain is probably a good example of conditioned pain
It’s a dangerous game diagnosing anyone’s pain as psychological or “just a perception,” because there are so many hard-to-diagnose organic conditions that do cause long-term pain (the sensation).3 One of the worst things any healthcare professional can do is imply that a patient’s pain is their “fault” in any way. But I’m not prepared to be so extreme with that caution that I ignore reality.
The uncomfortable truth — for every compassionate person, patient or pro — is that there is indeed such a thing as psychosomatic illness, disability, and pain. The functional neurological disorders (FND, formerly “conversion” disorders) are the most dramatic example of the extraordinary power of the mind to make us suffer. They are all too real.
If such dramatic psychosomatic symptoms exist, then they also exist in smaller doses — one ingredient in a pain cocktail.
It’s quite clear that these symptoms are a kind of “behaviour,” and equally clear that many of them are predictably triggered by specific non-painful stimuli. And this is a fairly obvious extension of the universal human experience of physical responses to psychological stimuli.4
Blushing occurs when the blood vessels of the head and neck dilate and become infused with blood. It is an instantaneous physical change seen on the surface but reflecting a feeling of embarrassment or happiness that is held inside. When it happens I can’t control it. That point is important. My blushes betray a feeling and, even when they increase my embarrassment, I cannot stop them.
It's All in Your Head, by Suzanne O’Sullivan, 3
We can extrapolate from “I always blush in this situation” to “I always hurt in this situation.” The undeniable existence of the former suggests that it pain could also sometimes be a conditioned response.
Another perspective on this is that psychosomatic symptoms are basically just a form of anxiety disorder… and anxiety as a classically conditioned response is already a well-established idea.5 And I know how this can go from personal experience, alas.6
Threat hyper-vigilance as a major driver for pain as a conditioned behaviour
Bear with me: this is a bit roundabout, but it’s a fun analogy. Pets are selected both naturally and artificially for snack hyper-vigilance. Hoomans are a good source of food. When we deliver the goods, our pets care about the context in which it happened way more than we do: every nuance is remembered, many subtle sensory details we are completely oblivious to.
Like the spot you were standing in when it happened.
Thanks to artist Jimmy Craig of TheyCanTalk.com for granting permission to use this perfect, poignant illustration of snack hypervigilance.
They remember… and then they watch for the signs! Intensely! You never know how a snack will happen, but it’s most likely to happen much like it has before.
Like pain! You can see where this is going.
How our brains are like that cat
Our animal brains do this too, obsessively filing away every detail they can about the circumstances of rewards… and threats. Definitely threats, too. If brains could talk, they would regale us with all the absurdly specific and subtle details they remember about past threats and rewards. It’s probably most of what’s going on under the hood for most animals, most of the time.
When something hurts a lot, our brains pay Very Close Attention to how it happened, and then we spend a long time “watching for the signs.” And yet, weirdly, we are mostly oblivious to those signs. Our conscious minds are filled with all kinds of wonders and nonsense. But our brains? Our brains are as focused as that cat:
“Remember when I stood in that exact way and I was in terrible pain?” the brain asks. The mind is barely even paying attention.
“I do,” says brain, and of course it does. Pain is most likely to happen much like it has before, and our brains know it even when we don’t. How much are we puppets of threat hyper-vigilance? Is it part of the mechanics of how pain works?
Threat hyper-vigilance is well-established psychology. The reality of it does not mean that pain can actually be conditioned… but, if pain can be conditioned, it’s probably because threat-hypervigilance is a potent force. If we do learn to hurt, it’s probably because our brains recognize the circumstances of past pain… and helpfully “warn” us about it … with more pain.
Disrupting the pain habit
Sensory Disruption of Reconsolidation (SDR) is an experimental chronic pain therapy method pioneered by Christine Sutherland, an Australian behavioural therapist and researcher. At first glance, SDR looks like exactly the sort of thing I am likely to scoff at: a treatment modality based on an extraordinary claim, namely that true chronic pain mostly consists of conditioned responses of the brain and central nervous system, and that these conditioned responses can be “extinguished” rapidly and permanently.
The brain is quite “plastic.” What is learned might be un-learned. Or disrupted.
If that’s true, it would be a big deal! So I am not a “believer” in SDR — not without evidence! — but I have been persuaded to take it seriously. I have been convinced by her humility and intellectual honesty, demonstrated to me in many emails over many months. This is a rare example of a treatment modality founder who absolutely understands that her method is experimental. For instance, she clearly understands that therapists tend to over-estimate their own efficacy.7 — but also thinks it’s an interesting and worthwhile experiment. And I agree.
Few pain treatments work out, and SDR could easily fail when tested in a rigorous trial. (A trial is in development right now, and is now seeking participants. It isn’t geographically limited, so you can apply no matter where you are in the world if you’re otherwise eligible.) Meanwhile, it has fascinating foundations and it’s something I want PainScience.com readers to know about and try if they have the chance.
Exactly what SDR looks like
SDR consists of exposure to highly specific conditioned stimuli associated with the pain experience, such as specific thoughts or perceptions link to the pain — language, metaphor, meaning, beliefs, etc — while simultaneously introducing disruptive sensory stimulation (literal and/or imagined). Now in more detail:
- A lot of chronic pain may be a learned response (classical conditioning) to harmless stimuli, and can be unlearned quickly and easily in principle, with a kind of mental hack: “disruption of the reconsolidation phase of the response.”
- “Reconsolidation” refers to the neurological process of regenerating a link between a stimulus and a behaviour. And that process can be disrupted by juxtaposing the conditioned response with a strong sensation — almost any sensation as long as it is a vivid one, with good timing. This disruption is a fairly well-studied phenomenon; when it occurs, reconsolidation fails completely the conditioned response simply ceases to exist. It’s like knocking the baton out of a relay racer’s hands just as they are passing it.
- So SDR therapy artfully evokes both reconsolidation and ways to disrupt it. A simplified example: focusing on thoughts and feelings that are precisely linked to the pain can trigger reconsolidation, and then it can be disrupted with contrasting behaviours and stimuli, such as a physical action (a slap, a hop, or a pinch), and visualization of a nice sensory experience (like petting your cat). The conditioned response has to be “caught in the act” of reconsolidating. If reconsolidation isn’t occurring, there is nothing to disrupt!
- The results of this process can seem simple, but getting it right is a lot like a plumber who solves a problem “easily” by knowing exactly what to do. For most people, disruption can only be achieved in a context of more comprehensive therapy — it takes real skill to identify and guide people through the identification and exploration of their triggers, and finding and interjecting the most apt and practical disruptive factors, and with good timing.
- And that’s not all! Pain is complex, and the more entrenched and severe it is, the more finicky this process can be. So SDR therapy also involves more conventional approaches to pain chronicity, by addressing major risk factors like sleep dysfunction, stress, poor nutrition. None of these are what makes SDR unique, but they are still important.
Similar to EMDR, EFT, NLP? Nope! Several things SDR is not
SDR is superficially similar to Eye Movement Desensitization and Reprocessing, Emotional Freedom Technique, and Neuro-Linguistic Programming — all notoriously dubious psychotherapeutic modalities that skeptics have been warning people about for a long time. But the theory and principles of SDR are not the same. Christine says that she was once “one of the ‘energy psych’ crew, so I understand their perspective, as much as it frustrates me at times.” But she left that world behind, and SDR is a different kettle of fish.
SDR is also often confused with “distraction,” “desensitization,” “inhibition,” “habituation,” or “exposure therapy.” These all related or similar concepts, but none quite captures what’s going on with SDR. It’s important to understand that disruption of reconsolidation is a specific neurological phenomenon and quite obscure.
DIY SDR? Can you do this for yourself?
Mostly no — too many cases are too complicated and difficult. An expert guide is probably needed for any result in most cases, let alone best results. And, of course, finding someone trained in SDR therapy to help you is probably going to be difficult. This isn’t a well-known modality.
The primary utility of this information for my readers is mostly just that it has some interesting implications for how chronic pain works, knowledge that is inherently valuable. It is good to know things. (“It’s what I do. I drink and I know things.” ~ Tyrion Lannister)
That doesn’t mean you can’t try some self-serve SDR though. Here’s the DIY version:
- Study your pain. Keeping this technique and the phenomenon of classical conditioning in mind, explore your experience. This phase could go on for days or weeks. Your ultimate goal is to trigger reconsolidation so that you can disrupt it: to actually recreate the link between a trigger and the pain. Therefore, you need to understand your triggers as well as possible. And they could be subtle! Once you believe you have a fairly good idea what constitutes a conveniently reproducible trigger for your pain…
- Invoke reconsolidation as best you can. This is a quick step, taking a few minutes at most. You focus on the trigger and the feelings you expect/fear it will create. This is largely a mental/meditative process, but could also involve an action or physical situation. And then, when you judge that you are right in the middle of rebuilding the link between the trigger and the pain…
- Disrupt reconsolidation! Like continuing to stir a sauce while adding a new ingredient, continue to focus on the link but mix in something completely different: a physical action, a vivid sensation, probably something pleasant, probably something functional.
- Repeat at semi-regular intervals. A sensible “dosage” might be twice a day for a week. Less risks failure due to simply not having enough disruption. More risks wasting too much time and energy on a highly experimental treatment.
Finally, do not neglect the broader context of your chronic pain! This is all probably doomed to failure if it’s done in a therapeutic vacuum. Nearly every chronic pain patient is dealing with extensive stresses and vulnerabilities. It’s important to tame those as well as you possibly can, both for the sake of this experiment and because it’s important for chronic pain patients regardless of SDR.
Completely unscientific anecdote
Clearly the DIY approach could easily fail even if professionally guided SDR proves to be genuinely effective. But I wouldn’t hesitate to try it myself if I needed to… and I have, and it worked extremely well. In only about three sessions, I “nuked” an extremely persistent case of hip pain (greater trochanteric pain syndrome). It had been unrelenting for months and had started to interfere with sleep. This was not a subtle or erratic pain that might have just happened to have backed off by chance or with a little optimism. It was a serious problem that evaporated more or less immediately after I took a swing at it with SDR.
It seemed remarkable, and that experience is probably chiefly responsible for the energy I’ve put into this article. Although I was intellectually interested before that, relief from a really nasty hip pain was quite inspiring.
About Paul Ingraham
I am a science writer in Vancouver, Canada. I was a Registered Massage Therapist for a decade and the assistant editor of ScienceBasedMedicine.org for several years. I’ve had many injuries as a runner and ultimate player, and I’ve been a chronic pain patient myself since 2015. Full bio. See you on Facebook or Twitter, or subscribe:
- 34 Surprising Causes of Pain — Trying to understand pain when there is no obvious explanation
- Anxiety & Chronic Pain — A self-help guide for people who worry and hurt
- Sensitization in Chronic Pain — Pain itself can change how pain works, resulting in more pain with less provocation
- Pain is Weird — Pain science reveals a volatile, misleading sensation that comes entirely from an overprotective brain, not our tissues
- Mind Over Pain — Pain can be profoundly warped by the brain, but does that mean we can think the pain away?
- Vulnerability to Chronic Pain — Chronic pain often has more to do with general biological vulnerabilities than specific tissue problems
- The 3 Basic Types of Pain — Nociceptive, neuropathic, and “other” (and then some more)
- Pain Relief from Personal Growth — Treating tough pain problems with the pursuit of emotional intelligence, life balance, and peacefulness
What’s new in this article?
Jul 31, 2021 — New section about threat hyper-vigilance, with a cool analogy to pet reward hyper-vigilance.
2020 — Proofreading.
2020 — Added evidence that chronic pain can be a conditioned behaviour, plus some reading recommendations.
2020 — Publication.
- Flor H. New developments in the understanding and management of persistent pain. Curr Opin Psychiatry. 2012 Mar;25(2):109–13. PubMed #22227632 ❐
This paper describes the evidence for chronic pain as a conditioned response.
- Simons LE, Moulton EA, Linnman C, et al. The human amygdala and pain: evidence from neuroimaging. Hum Brain Mapp. 2014 Feb;35(2):527–38. PubMed #23097300 ❐ PainSci #52566 ❐
This paper explores some of the key neurobiological support for chronic pain as a conditioned behaviour.
- Ingraham. 34 Surprising Causes of Pain: Trying to understand pain when there is no obvious explanation. ❐ PainScience.com. 14630 words.
- O’Sullivan S. It's All in Your Head: True Stories of Imaginary Illness. Chatto & Windus; 2015.
This book consists mainly of well-told stories of severe psychosomatic illness and functional neurological disorders (neurological symptoms without diagnosable disease). The key take-away is that psychologically powered illness is common and can be amazingly severe. Although Dr. O’Sullivan is clearly concerned about the risk of incorrect diagnosis, and she is cautious and compassionate enough that I think she mostly gets it right (with the notable exception of the chronic fatigue chapter). It’s well-written and fascinating and has plenty to offer. I do wish there were citations.
- Anxiety is not a well defined part of the human experience, and never has been. People have been arguing about its nature for millenia: is it a philosophical problem or a biological one? Driven by nature or nurture? Congenital or acquired? Anxiety disorder is well described, but not well understood. One possibility that has been taken seriously by many experts for decades is that it is a classically conditioned behaviour: a learned response to things that shouldn’t be so scary. When anxiety is about our health (hypochondria), we can easily generate a wide variety of psychosomatic symptoms that are terrifyingly real to the victim. So we can probably learn to experience symptoms as a response to all kinds of subtle cues — and one of those symptoms can be pain. Therefore, if anxiety can be a conditioned response, so can pain.
In 2015, I had a rough time with withdrawal from an accidental addiction to benzos. Benzo withdrawal can cause both strong anxiety and bizarre, hallucinatory symptoms. I suffered greatly, reacting fearfully to strange sensations dozens of times a day for weeks. My standard reaction was basically “that sinking feeling,” a swoon of dread, but the swoon became just another symptom to be afraid of: rather than perceiving it as fear, I experienced it as a woozy, sickly exaggeration of whatever little sensation triggered it. Small ordinary pains almost instantly turn into bigger, weirder ones. It’s basically exactly like being alone in a scary old house and overreacting to every noise and shadow, perceiving what you fear rather than what is actually there.
The withdrawal slowly eased, but the damage was done: I had learned to respond to odd sensations with nervous reflections of them, many of them painful.
- Tracey TJ, Wampold BE, Lichtenberg JW, Goodyear RK. Expertise in psychotherapy: an elusive goal? Am Psychol. 2014 Apr;69(3):218–29. PubMed #24393136 ❐
I know Christine knows this, because I got this reference from her. She summarized it in one of her own papers about SDR: “therapists tend to over-estimate their expertise, and also over-estimate effect size (if any) of the treatments they provide.” Yep. Exactly right! And that’s the kind of humility and self-awareness that earned my trust.