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What did you expect?



The 2024 Global Year will examine what is known about sex and gender differences in pain perception and modulation and address sex-and gender-related disparities in both the research and treatment of pain.

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Hands-up who thinks a patient’s expectations influence how well they do in treatment?

By Steve Kamper

Nearly everyone? That’s no surprise. Research recently published by a group in the US reported on the relationship between expectation and outcome in a sample of back pain patients receiving physiotherapy. This is by no means the first time this link has been reported; numerous previous studies have reported similar findings across many different types of conditions. This is also this same relationship that provides the most widely-accepted explanation for placebo effects (sometimes called non-specific treatment effects). Outside the research setting, clinicians recognise the association between expectation and outcome and try to pass on a feeling of confidence and positivity, even if, at times they know the treatment itself is ineffective [1].

It all sounds pretty rosy, just pump up the expectation volume and you get extra bang for your treatment buck. But what if the expectation/non-specific effect is all you are getting? Even some medications that we ‘know’ are effective analgesics can have negligible effects when administered without the patient’s knowledge [2]. Given that placebo interventions attempt to control for patient expectation; maybe this is why RCTs report such small effects for so many commonly used treatments [3]. However, if we buy into this argument, are we reducing our clinical practice to little more than 21st century witch-doctory? For someone like myself with a background in physiotherapy, the thought is a little disconcerting. And I’m not alone, whole therapeutic professions have had to defend themselves against this accusation [4].

On the other hand, does it matter at all? If the people who come through the door (mostly) end up getting better and they are satisfied with the service, is their time/money not well spent? [5] As long as the patient knows what they’re getting and how much it’s going to cost and the clinician seeks to attain to the best outcome, everything’s hunky-dory. Maybe…

Regardless of where you stand on the specific effects of any particular treatment though, it is probable that disregarding the effects of patient expectation will result in suboptimal outcomes for patients. Just as apparent though is that, for the most part we’ve bugger-all idea about how to use this information. Much has been locked up in the black box marked ‘Placebo’ which, it could be argued has been/continues to be a hindrance to understanding and harnessing non-specific effects (see [6] for an excellent discussion on this topic).

There is no shortage of questions that are awaiting our attention. Are the patients with high expectations of doing well the ones that just aren’t very sick? Are ‘expectations’ just measuring how optimistic someone is generally? How do people come by their expectations? Can clinicians change them, and if so, how? How do expectations influence outcome, is it a direct effect or indirect via something else, like improving treatment adherence?

The idea that we can piggy-back enhanced expectation effects onto whatever treatment we choose is a seductive one, it offers the promise of additional benefit for lots of patients with all different types of conditions. If we can just find the right key (or sledge-hammer) to open the placebo black box we just might find that it is full of tasty goodies.

About Steve Kamper

Steve’s career as an Environmental Scientist was cut short due to an inability to grow dreadlocks or a convincing beard; he changed to Physiotherapy after being told he looked handsome in a polo shirt. He is currently enjoying the fancy restaurants and 4-day weekends that accompany the life of a PhD student at the George Institute for International Health in Sydney. Steve’s research to date has involved investigation into subjective outcome measures and placebo effects, particularly in patients with whiplash and low back pain. Leisure time is spent playing soccer, running and doing push-ups in his Speedos at the beach.


[1] Tilburt JC, Emanuel EJ, Kaptchuk TJ, Curlin FA, & Miller FG (2008). Prescribing “placebo treatments”: results of national survey of US internists and rheumatologists. BMJ (Clinical research ed.), 337 PMID: 18948346

[2] Amanzio M, Pollo A, Maggi G, & Benedetti F (2001). Response variability to analgesics: a role for non-specific activation of endogenous opioids. Pain, 90 (3), 205-15 PMID: 11207392

[3] Machado LA, Kamper SJ, Herbert RD, Maher CG, & McAuley JH (2009). Analgesic effects of treatments for non-specific low back pain: a meta-analysis of placebo-controlled randomized trials. Rheumatology (Oxford, England), 48 (5), 520-7 PMID: 19109315

[4] Singh S, Ernzt E (2008). Trick or treatment. Alternative medicine on trial. Bantam Press, UK.

[5] Hush JM, Cameron K, Mackey M (2010). Patient satisfaction with musculoskeletal physiotherapy: A systematic review. Under review at Physical Therapy.

[6] Nunn, R. (2009). It’s time to put the placebo out of our misery BMJ, 338 (apr20 2) DOI: 10.1136/bmj.b1568

All blog posts should be attributed to their author, not to BodyInMind. That is, BodyInMind wants authors to say what they really think, not what they think BodyInMind thinks they should think. Think about that!

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