Why reducing pain intensity doesn’t always mean a better outcome

There have recently been some studies published on meta-analyses of “pain education”. I’ve made my stance clear on what I think of “pain education” particularly as a stand-alone intervention here and here and why I think we need to look beyond pain intensity reduction as The Outcome of Choice. In this brief post I want to look at some of the variables that influence both pain behaviour and pain intensity.

We all know that pain is subjective: this means it can’t be directly shared with anyone, and no-one is able to determine just how sore any other person is (that includes people who believe they can spot faking or malingering. Stop it! You can’t, not for pain). What this also means, though, is that for us as clinicians to understand what it is like for another person to be experiencing pain, we must infer on the basis of what they do (ie behaviours).

Mostly with adults, we infer the severity of pain on the basis of the dreaded visual analogue scale or the numeric rating scale – “what is your pain on a 0 – 10 scale where 0 = no pain at all and 10 = most extreme pain you can imagine.” In people who either don’t speak our language, or who can’t respond with words, we rely on inferences drawn from their “body language” or nonverbal behaviour.

Many pain behaviours begin as useful evolutionary responses to threat: physiological arousal, reflex withdrawal, verbal groans and gasps. These serve to help us withdraw from the stimulus, help us escape the threat (or freeze or fight it), and signals that we need help (and avoid this threat) because we’re social animals. At the same time, behaviours are subject to behavioural reinforcement as well as cognitive biases, memories and so on. An example: If someone goes to the Emergency Department and reports their pain is 3/10, they’re unlikely to receive heavy-duty analgesia. You can bet that if they attend ED on another occasion, they’ll remember this and report their pain to be a little higher. Now often this isn’t a conscious decision, it’s something we learn over time and throughout our lives, so we may be oblivious to how we alter our verbal and nonverbal behaviour as a response to events in the environment and our own interpretations of what’s going on.

Pain is also rarely a static, consistent experience. Pain typically varies over the course of time. It can be episodic and pulsing and rhythmic, or it may come in waves, it might fluctuate unpredictably: in part this variability is a product of the stimulus, but also physiological processes such as habituation, attentional demands can mean we’re more or less “tuned in” to being aware of pain, and our emotional state is also part of the picture.

Finally (or not, depending on my whim!), our response to pain depends on our interpretation of its meaning and significance. When we’re tired and feeling down, and the pain seems mysterious and very threatening because we have things to do and no-one can tell us what the diagnosis is we’re more likely to increase our awareness and our behaviour associated with that experience. Maybe we’ll report it as 9/10 because it seems to intrude on life, the universe and our very existence as we know it. Maybe we’ll be really afraid and don’t think we can cope with it even though we usually do, so we’ll report it as 12/10. Maybe we’re not experiencing pain right now but we think that if we do something wrong we’ll get the pain back (think of angina here), so we just don’t do things “in case”. And maybe we’ve been told not to do things because it might be harmful, so we don’t do those things, our pain is around its usual level but we feel constrained and report it as 7/10 because we’re fed up with it all.

We know that part of the challenge of pain is that it’s incompletely understood (I use the word “it” as a placeholder for the rather more wordy “our experience of pain”). We do have pretty good means of reducing pain, but the problem is that these leave us incapable of doing very much because the most effective approach is simply to lose consciousness. But life doesn’t permit us to do that for long without adverse consequences! And for many people, even the best analgesia is only likely to reduce pain by about 30%, if at all.

When someone has learned to reinterpret their pain as not terribly threatening, still annoying and frustrating and demoralising, but not indicating that the body/self is about to come to serious harm, it’s possible to look well but feel awful inside. In other words, the pain intensity and quality doesn’t change an awful lot, but because it’s no longer associated with existential threat to self, it’s possible to put on makeup, groom well, interact happily, and look “normal”. How do I know this? Well – that’s what I do every day.

So using pain intensity as a guide to how well a person has recovered or adjusted to their pain is not an especially reliable guide as to how much pain is bothering them. The relationship between pain intensity and what we can and cannot do is uncertain and complex. And behaviour change is not easy. Doing things differently involves a whole cascade of changes that need to be implemented, not the least of which is learning how to regulate physiological arousal, reconceptualising the pain experience as something that can be lived with, redirecting attention towards things that matter to us, developing motor control and strength when this has changed – but possibly the most complex and ignored involves responding to, or altering our response to other people’s behaviours.

This means navigating other’s expectations from us (some people are afraid that when a person begins doing things again they’re going to make their pain worse and fail, others are expecting return to “normal” without factoring in that pain IS a significant challenge to deal with), and their behavioural responses to what we do. Many of the people I work with who live with pain talk about losing friendships, not being able to keep up with others, being misunderstood, being ignored or punished with angry reactions because they’re not the same person they were before their encounter with weird prolonged pain. And these are only the responses at an individual and small group level! What about the perverse disincentives to return to usual activities, like losing compensation prematurely, or having to return to a job that is not the job you left and you feel unprepared for or overskilled and unappreciated? Legislation that is written for “normal” recovery from illness or injury but doesn’t include persistent pain. Processes that mean you have to prove disability repeatedly just to retain access to services or income.

So, even if clinicians find that their treatment reduces pain, it may not lead to the outcomes clinicians want to see: a happy, active and engaged person. Sometimes it can lead to ongoing life restrictions (think angina again). Sometimes it can lead to erratic activity patterns. Sometimes those other factors influence how the person goes about life and not in a good way.

Echoing something written repeatedly over the decades in pain research literature, I want to quote from Ballantyne and Sullivan (2015). This article challenges clinicians to rethink pain reduction as the primary outcome measure for persistent pain in the face of increasing opioid use (now reducing but often without subtlety or support) because of the very issues I’ve outlined above. They state the following:

Suffering may be related as much to the meaning of pain as to its intensity. Persistent helplessness and hopelessness may be the root causes of suffering for patients with chronic pain yet be reflected in a report of high pain intensity.

And conclude their article with this:

When pain is chronic, its intensity isn’t a simple measure of something that can be easily fixed. Multiple measures of the complex causes and consequences of pain are needed to elucidate a person’s pain and inform multimodal treatment. But no quantitative summary of these measures will adequately capture the burden or the meaning of chronic pain for a particular patient. For this purpose, nothing is more revealing or therapeutic than a conversation between a patient and a clinician, which allows the patient to be heard and the clinician to appreciate the patient’s experiences and offer empathy, encouragement, mentorship, and hope.

Emphasis is entirely mine. And heartfelt.

Ballantyne, J. C., & Sullivan, M. D. (2015). Intensity of chronic pain—the wrong metric? New England Journal of Medicine, 373(22), 2098-2099.