The positive power of what we say during treatment

Expectations form one of the important predictors of response to treatment, especially in the case of treatments for pain. A person’s belief or expectation that a treatment will reduce their pain is thought to be part of the response to placebo – and indeed, part of the response to almost any treatment.  Much of the research into expectancies has been carried out in experimental models where healthy people are given a painful stimulus, then provided with some sort of treatment along with a verbal (or written) instruction that is thought to generate a positive belief in the effectiveness of that treatment. The people we see in a clinical setting, however, are in quite a different setting – they experience pain sufficiently disruptive to their sense of well-being that they’ve sought treatment, they may not know what the pain problem is, they may have other health conditions affecting their well-being, and for some, their pain may be chronic or persistent. Do expectations have a clinically-relevant effect on their pain?

Luckily for us, a recent meta-analysis published in Pain (Peerdeman, van Laarhoven, Keij, Vase, Rovers, Peters & Evers, 2016) means the hard work of crunching through the published research has been completed for us! And given 15 955 studies were retrieved in the initial pass through the databases, we can be very relieved indeed (although only 30 met the inclusion criteria…).

What are expectations?

Before I swing into the results, it’s important to take a look at what expectations are and how they might relate to outcomes. According to Kirsch (1995) response expectancies are expectancies of the occurrence of nonvolitional responses (ie responses we’re not aware we make) as a result of certain behaviours, or specific stimuli.  Kirsch points out that nonvolitional responses act as reinforcement for voluntary behaviour, so that by experiencing a nonvolitional response such as relief, joy, reduced anxiety and so on, people are likely to engage in  behaviours associated with that experience again. For example, if someone is feeling worried about their low back pain, just by having a treatment they expect will help and subsequently feeling relieved, they’re likely to return for that treatment again.

How are expectations created?

Some expectations are generated within a culture – we expect, for example, to see a health professional to relieve our ill health. In general, simply by seeing a health profession, in our developed culture, we expect to feel relieved – maybe that someone knows what is going on, can give a name to what we’re experiencing, can take control and give direction to whatever should happen next. This is one reason we might no longer feel that toothache as soon as we step into the Dentist’s waiting room!

Peerdeman and colleagues outline three main interventions known to enhance positive expectations for treatment: verbal suggestion “You’ll feel so much better after I do this…”; conditioning “If I give you this treatment and reduce the painful stimulation I’ve been giving you, when you next receive this treatment you’ll have learned to experience relief” (not that you’d actually SAY this to anyone!); and mental imagery “Imagine all the wonderful things you’ll be able to once this treatment is over”.

I think you’d agree that both verbal suggestion and mental imagery are processes commonly used in our clinics, and probably conditioning occurs without us even being aware that we’re doing this.

How well does it work for people with acute pain?

As I mentioned above, expectations are used in experimental designs where healthy people are poked and zapped to elicit pain, and hopefully our clinical population are not being deliberately poked and zapped! But in clinical samples, thanks to the review by Peerdeman and co, we can see that there are quite some impressive effect sizes from all three forms of expectancy induction – g =  0.67 (95% CI 0.49-0.86). That means a good deal  of support from the pooled results of 27 studies to suggest that intentionally creating the expectation that pain will reduce actually does reduce pain!

And now for chronic pain

Ahhh, well…. here the results are not so good, as we’d expect. Small effects were found on chronic pain, which is not really unexpected – chronic pain has been around longer than acute pain, so multiple reinforcement pathways have developed, along with pervasive and ongoing experiences of failed treatments where either neutral or negative effects have been experienced.

What does this mean for us as clinicians?

Probably it means that we can give people who are about to undergo a painful procedure (finger pricking for diabetes, dressing changes for ulcers, getting a flu jab) a positive expectation that they’ll feel better once it’s over because the strongest effect was obtained for people undergoing a painful procedure who received a positive verbal suggestion that the procedure would help.

Chronic pain? Not quite so wonderful – but from this study I think we should learn that expectations are a powerful force in our treatments, both individually with the person sitting in front of us, but also socioculturally – we have an expectation that treatments will help, and that’s not something to sniff at. Perhaps our next steps are to learn how to generate this without inducing reliance or dependence on US, and on helping the person recognise that they have generated this themselves. Now that’s power to the people!


Kirsch, I. (1985). Response expectancy as a determinant of experience and behavior. American Psychologist, 40(11), 1189.

Peerdeman, K. J., van Laarhoven, A. I. M., Keij, S. M., Vase, L., Rovers, M. M., Peters, M. L., & Evers, A. W. M. (2016). Relieving patients’ pain with expectation interventions: A meta-analysis. Pain, 157(6), 1179-1191.


  1. ” … chronic pain has been around longer than acute pain, so multiple reinforcement pathways have developed, along with pervasive and ongoing experiences of failed treatments where either neutral or negative effects have been experienced.” Bronnie, I have a problem with your interpretation of the failure of expectations to significantly improve the predicament of the persistent pain sufferer. Is there any evidence for the existence of these “multiple reinforcement pathways”?

    1. Behavioural reinforcements for pain behaviours (which are, of course, the only aspect of pain that anyone apart from the person experiencing it can observe) have been studied extensively – so I’m referring to the associations between observable behaviours (including what people living with pain say, and what they do) and factors such as distress, hopelessness, thinking the worst, along with learning responses from having not been able to reduce the experience of pain that show consistent relationships. I don’t think there is a direct 1:1 relationship between what can be seen on fMRI and our experience of pain (and you’ll know this from things I’ve said previously) but I do think there are pragmatic and functional relationships between variables and both behaviours and neurological events that we can think of as current proxies for aspects of our pain experience.
      Given the imprecision with which anyone can measure any construct in this area, I think behavioural studies such as those carried out within relational frame theory can provide some evidence of the multiple associations that can occur just from the use of words. To give a really brief example, when we think of the word “free” we have many different words and concepts that we can associate with it – things like “on sale” or “joy” or “liberty” or even the converse “imprisoned”, “expensive”, “constrained”. Along with thinking of the words, we also experience emotions and often respond.
      Drawing from research into PTSD where many different stimuli can act as triggers for the experience of panic and despair associated with PTSD, we can see that learned associations can form in relation to the previous event (recalled from memory), encountering items that were present at the time of the initiating event, encountering items that remind the person of similar items that were present, even words or pictures of stimuli that were present at the time of the event can trigger a physiological response. And many of these responses are not available to conscious thought – they occur “under the radar” and to the individual might “just happen out of the blue”. As a consequence the person experiencing PTSD may avoid situations without realising why.
      I see similar parallels with the experience of chronic pain – it’s relatively easy to suggest to someone who has an acute pain (and therefore not many associations between experiencing pain and the stimuli present at the time) that they’ll be fine, because it’s easier for that person to inhibit or downregulate the relatively small number of neural pathways that are active. A person who has been living with chronic pain has multiple associations between stimuli and their experience – it’s pervasive, can occur in many different locations, in association with many different stimuli – and research suggests that we don’t tend to lose those neural associations quickly, rather we learn to make new associations that are subsequently strengthened as we repeat the same connections.
      I’m not terrific at articulating the neurobiology behind associative learning, but I would highly recommend reading Mastering the Clinical Conversation by Villatte, Villatte & Hayes (2016), The Guilford Press, and anything in the relational frame theory research literature for the underlying basis of this approach to understanding human experience and behaviour.

      1. Bronnie, are you going down the same blind alley as Moseley & Vlaeyen (2015), who hypothesised that chronic pain was “a conditioned response to the multisensory and meaningful events that routinely coincide with, or preempt, nociceptive input”?

        We were unable to find any evidence to support this hypothesis.

        But there is overwhelming evidence that “fear” rather than “pain” is the conditioned response.

        Reference: Moseley GM, Vlaeyen JW. Beyond nociception: the imprecision hypothesis of chronic pain. Pain 2015; 116: 35-37.

      2. No, I don’t think so – I’ve talked about pain behaviours, and associations between the experiences we have (emotions as well as the experience of pain) and what we do about them, and also what we associate with them – verbal utterances are also behaviours (even when those verbal utterances are unvoiced but are thoughts). One of my points is that we can “defuse” from automatically (ie a conditioned response) judging pain-as-an-experience as negative-therefore-to-be-avoided. Many people do this when they pursue painful experiences such as body suspension (where the pain is judged as representing part of a process of achievement), or having a joint replacement (where pain is judged as something to go through as part of getting to walk without pain). Does this make sense? I really do think it’s worth reading about RFT to get a good feel for what I’ve so clumsily explained.

  2. I think this ties in well with the therapeutic alliance we create with patients. We know that a good alliance shows better outcomes (Hall A. et al 2010). When we have a better alliance I suspect that patients are more apt to believe in what we say and when we are positive they too can feel more open to accepting our advice and are more compliant creating better outcomes. I think we will find this somehow all works together.

    1. A clinical encounter can have a successful outcome for both participants when they choose to actively engage in a communicative process to search for meaning. Each puts forward an interpretation of the world, through both language and actions. Both will freely acknowledge that everything that is said and done during the encounter is imbued with meaning, and both will be prepared to admit where their knowledge and understanding is deficient. Based on the knowledge, experience, habits, expectations, and vulnerabilities that each brings to the meeting, participants can negotiate to build an intersubjective world from which shared meaning can emerge. This world is also known as the “third space”.

      1. John, I agree – that’s why I think learning communication skills must be elevated above what’s learned in the first year of training… but people are not just looking for meaning, they’re also looking for solutions and to live the life they want. Negotiating that part is even more of a challenge especially given the relative lack of importance placed on being with rather than doing to (in terms of funding). Healthcare is funded on the number of procedures undertaken rather than the outcomes obtained, or even the process of getting to an outcome. And communication is not easy because it means becoming vulnerable, not something anyone likes to do.

      2. Yes, it does need to be said that both clinician and patient are vulnerable during an intersubjective engagement. Both are grappling with the same aporia – that of pain. The stakes they are playing for are high and the risks for both are not inconsiderable. Each is seeking validation from the other and both are seeking solutions. But, as we know, our current systems of healthcare funding do not cater for intersubjective negotiations. In fact they seem to actively discourage health care professionals from undertaking them. I apologise for ending this comment on such a pessimistic note.

      3. I agree JQ, I think incentivising healthcare as if it’s some sort of production line is anathema to connecting and valuing interactions. Do you think a focus on outcomes might help? or does this risk focusing on easily-counted outcomes such as return to work?

      4. Bronnie, there is some good news for New Zealanders. Dr Kristin Good, Senior Medical Advisor, Accident and Compensation Commission (ACC) met recently with the Board of the Faculty of Pain Medicine, ANZCA. Pain Medicine services in NZ were discussed, as was the opportunity for further cooperation between these two organisations. One would hope that the ACC will seek to rectify the horrible mistake it made some time ago when it effectively disenfranchised those with work-related cervico-brachial pain syndromes:

    1. All I can say is that to date there have been almost 3,000 hits on Fibromyalgia Perplex in relation to this article. Perhaps the message is now getting through!

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