Can Contextual Factors Improve Clinical Outcomes?
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Years ago I heard about the impressive results from placebos in several clinical trials and decided to explore the subject further to see if it was something that I, as a massage therapist, should know more about. The first book I read was The Placebo Response[i], by Howard Brody. This was an interesting read because it was actually written for the patient, in other words, with full disclosure. By the time I had finished his book I realized that the mysterious placebo was a bit less mysterious than one might think. It was soon afterward that I decided to write a book to guide manual therapists through the murky waters of the placebo effect. After reading another dozen books and 300 studies on this topic I finally felt that I had gathered enough information to complete the project. Since writing a book was a part-time venture, many years would pass before its completion. Fortunately, by that time the biopsychosocial model[ii] was gaining increasing acceptance as a more inclusive way to understand human health, pain and healing, making the concept of placebo (aka contextual) factors far more mainstream than they once were. Current research into the placebo effect is helping to inform the psychological and the social components of the biopsychosocial model. One place where this phenomenon is being studied earnestly is Beth Israel Deaconess Medical Center at Harvard Medical School. There the Program in Placebo Studies and the Therapeutic Encounter (PiPS) is examining the following areas to examine their contribution to the placebo effect:
- Patient-Oriented Clinical Research
- Research in Neuroscience and Molecular Biology
- Research in the Social Sciences
- Research Methodology
- Initiatives in the Humanities and Bioethics
If you search PubMed Central® (PMC) at the U.S. National Institutes of Health’s National Library of Medicine using term “placebo effect” and ask for year-specific results, you will get a total of two papers in 1972. That number began rising consistently over subsequent decades. Last year (2015), three hundred and twenty papers were published containing the term “placebo effect”’. There are now over 5000 papers in PMC’s database that either examine, or mention this phenomenon in the study. There are other MeSH terms that are used to describe this phenomenon as well. Two of the more popular terms are “non-specific effect” (325 total results) and “context effect” (241 total results). Clearly the research community is standing up and taking notice of the lowly placebo. When you consider the number of returns for the individual search terms you will understand why I often use the term placebo effect to describe this phenomenon, because it is by far, the most popular MeSH term.
So what have these many studies revealed? Experts have grouped the triggers for this phenomenon into three main categories: conditioning, expectation and meaning. The first two are the most well-studied and well-established contextual triggers. The third category, ‘meaning’ is complex and multi-faceted. Meaning, as a concept is so important that medical anthropologist Daniel Moerman considers any placebo response to be what he terms, ‘the Meaning Response’[iii]. Other authors have different pet terms for this phenomenon. For example respected researcher Fabrizio Benedetti has used the term ‘Endogenous Healthcare System’. A few of the dozen other terms include ‘Hope Effect’ and ‘Belief Effect’. While we obviously won’t see agreement on the best term to use in a clinical environment any time soon, there is a growing consensus that psychosocial factors affect healing outcomes as well as the client’s interpretation of pain.
A graphic representation of what might be going on with the placebo effect would look a little like Figure 1. A psychosocial trigger can up-regulate or down-regulate a biological pathway, which then creates an effect. We see subjective effects such as changes in pain perception and patient descriptions of wellness states, but also objective changes such as improved function, tissue and blood pressure changes, increases in dopamine levels and natural killer cell function to name a few. Some of these changes are temporary, but some can last the entire duration of the study.
The list of psychosocial triggers that I found to be supported by varying degrees of evidence[iv] included the following:
- Expectancy (including Belief, and Hope)
- Motivation and Desire
- Feeling listened to
- Care and concern
- Establishment of a feeling of control
- Reducing patient anxiety levels
- Giving adequate explanation
- The importance of the patient’s inner narrative
- Acceptance of the mystery of healing
- Certainty of patient
- Effective use of treatment time
- Clinical environment
- Use of ritual
- Use of touch
- Use of humour
- Clinician’s Persona
- Clinician’s belief system
- Perceived competence
- Projected confidence
- Your Attire
- Your Enthusiasm
The first concept, ‘expectancy’ also includes such concepts as belief, and hope. While each of these concepts is slightly different, from a research point of view they have largely been grouped together. This concept is one of the most studied triggers of the placebo effect[v]. Patient expectations are extremely important, and this is why you need to be careful of your wording when interacting with your client. One should always err on the side of positive when projecting clinical outcomes, and it is also important to keep the door open to full recovery. While limbs are not going to grow back, and paraplegics are not going to walk, history has thousands of examples of people who proved their doctor wrong after being told they would never walk, or talk, or play sports again. It is quite amazing what a well-motivated patient can do. As you can see from the list, motivation is another trigger for this effect.
Something worth mentioning before leaving the topic of expectations is the nocebo[vi] effect. We are all required to give our clients proper informed consent. This means listing any and all side effects of a given treatment or modality. Be aware that mentioning a negative side effect opens to door to the nocebo effect, the exact opposite of the placebo effect. The best way to mitigate this effect is to give your client a protocol, or a suggestion for minimizing any side effect that might happen. This helps to put their mind at ease, should any symptom occur, thereby minimizing any nocebo response.
Conditioning is another well-studied trigger of this healing phenomenon. This can be either positive or negative conditioning. Your patient might arrive at your door already positively conditioned to your modality (thanks to another practitioner), or the reverse could also be true. Either way, you should be able to gather this information while taking their medical case history. This will give you clues as to what to say to either build upon previous positive conditioning, or minimize and redirect negative conditioning. It is worth mentioning that placebo conditioning is not limited to humans. Conditioning studies dating back to the 70s were performed on animals, and these revealed results such as immune cell suppression[vii], and blood pressure alteration when a placebo was linked to active medications, and then administered separately at a later point in time. This is particularly interesting in that we often assume that the placebo effect is a human phenomenon. Placebo conditioned responses in both human and animal models tend to follow classic Pavlovian conditioning models, meaning that there is an eventual diminishing of the placebo effect if the treatment schedule does not include an active agent at least 30% of the time.
The remaining concepts or triggers (from ‘trust’ onward) could be grouped under the heading of meaning. In other words, your patients are either consciously or unconsciously saying to themselves, “What does this experience, or event mean to me?”. As you can see, this list is extensive and I devote a complete section to each one of these concepts in the book, offering therapists practical ways to incorporate each of these ideas ethically into their daily practice. At the very least, each concept could easily be the topic of a future article. We do not have the time or space here to delve into each of these triggers at this time, but you will notice that the last item on the list is the clinician’s persona. Another way to look at this is that you are the placebo. The more competent you are; the more professional you act- the greater your professional impact will be on the patient, and this will translate into improved outcomes. Your persona is not exactly ‘you’. Hopefully it is a better version of you. Crafting your professional demeanour is a lifetime pursuit, but hopefully your professional persona is, for example, more patient, more punctual, more empathetic, and a better listener than you might be. This professional demeanour helps to enhance the contextual or placebo response that is a natural by-product of the professional relationship that you have with your client.
Before leaving this extensive list, let me just remind you that trust is the foundation of any and all relationships (human or otherwise). Anything that you do to build trust with your client has the possibility of increasing the placebo effect. Conversely anything that undermines that trust will most surely minimize and potential symbolic effect that you may carry as their health practitioner.
Conditions Most-Affected by Placebos
Placebo responses vary quite markedly in clinical studies, and some conditions are unresponsive to placebos. The good news is that placebo responses are quite strong in conditions that massage and manual therapists treat (pain, inflammation, and function). The most concentrated research on the placebo effect has looked at the neurobiological mechanisms of the placebo response around pain and analgesia. There are also new placebo models emerging around the respiratory and cardiovascular system, the immune and endocrine system, Parkinson’s disease, and depression.[viii] Placebos have also been studied and play a role with asthma, Crohn’s disease, ulcers, IBS and arthritis. However, strong responses are seen in the sorts of conditions that manual practitioners work; specifically pain, inflammation, and function. A 2008 meta-analysis of osteoarthritis studies looked at 198 trials with 193 placebo groups (16,364 patients) and 14 untreated control groups (1167 patients). This study concluded, “Placebo is effective in the treatment of OA, especially for pain, stiffness and self-reported function.”[ix] While it might seem surprising or counter-intuitive, strong placebo responses have actually been seen with inflammatory responses[x] as well. Improvements in patient function are perhaps less surprising, since there is a conventional wisdom that a component of this could involve mind over matter.
What Role do Placebo Effects Play in Manual Therapy?
Several systematic reviews in recent years have looked at the role of this phenomenon in manual therapy and the conclusions have overwhelmingly been that these effects are ubiquitous. Furthermore, conclusions from these analyses recommend that therapists should acquaint themselves with the psychosocial factors that trigger this effect, firstly to enhance clinical outcomes, but secondly to avoid producing unintended nocebo responses. Three current reviews[xi] that look at this subject and are well worth reviewing are:
- ‘Enhance placebo, avoid nocebo: How contextual factors affect physiotherapy outcomes’ (Testa and Rossettini, 2016),
- ‘Placebo response to manual therapy: something out of nothing?’ (Bialoski. 2011), and
- ‘Effectiveness of manual therapies: the UK evidence report’ (Bronfort, 2010).
What is well-established is that placebo effects are coming into play in virtually all medical encounters from simple consultations to surgery[xii]. As a practitioner it would behoove you to become more conversant in this subject. Understanding psychosocial factors that affect treatment outcomes is an important part of being a professional practitioner. Employing techniques such as active listening, motivational interviewing, and reducing patient anxiety levels are not a substitute for technical competency; they are an adjunct to your manual techniques. Understanding these factors will make you a better therapist and can improve clinical outcomes.
 Note that these numbers all relate to searches for the phrase “placebo effect” in quotations. A search for the term placebo effect (not in quotations) returns dramatically higher numbers (total 74,367 results on June 20, 2016 versus 5,406 for “placebo effect”).
 MeSH (Medical Subject Heading) is the National Library of Medicine’s controlled vocabulary thesaurus. It consists of sets of terms naming descriptors in a hierarchical structure that permits searching at various levels of specificity. https://www.nlm.nih.gov/mesh/
[i] Brody, Howard. The Placebo Response: How You Can Release the Body’s Inner Pharmacy for Better Health. New York, New York. HarperCollins, 2000.
[ii] Borrell-Carrió, F. Suchman, A., Epstein, R. (2004) The Biopsychosocial Model 25 Years Later: Principles, Practice, and Scientific Inquiry. Ann Fam Med. 2004 Nov; 2(6): 576–582.
[iv] Fulton, B. Placebo Effect in Manual Therapy. Improving Clinical Outcomes in Your Practice. Edinburgh, United Kingdom. Handspring Publishing, 2015.
[v] Price, D.D., Finniss, D.G., Benedetti, F. A comprehensive review of the placebo effect: recent advances and current thought. Annu Rev Psychol. 2008;59:565-90
[vi] Testa M, Rossettini G. (2016) Enhance placebo, avoid nocebo: How contextual factors affect physiotherapy outcomes. Man Ther. Aug;24:65-74.
[viii]Colloca, L et al. (2005) The placebo response in conditions other than pain. Semin Pain Med. 3:1;43–47
[ix] Zhang, W. et al.(2008). The placebo effect and its determinants in osteoarthritis: meta-analysis of randomised controlled trials. Ann Rheum Dis. 67:1716-1723
[x] Hashish, I., H.K Hai et al. (1986). Reduction of postoperative pain and swelling by ultrasound treatment: a placebo effect. Pain 33: 303-311
[xi] Testa M, Rossettini G. (2016) Enhance placebo, avoid nocebo: How contextual factors affect physiotherapy outcomes. Man Ther. Aug;24:65-74.
Bialosky JE, Bishop MD, George SZ, Robinson ME. (2011) Placebo response to manual therapy: something out of nothing? J Man Manip Ther. Feb;19(1):11-9.
Bronfort, G., Haas, M., Evans, R. et al. (2010) Effectiveness of manual therapies: the UK evidence report. Chiropr Osteopat. 18: 3.
[xii] Wolf, B.R., Buckwalter, J.A. (2006) Randomized Surgical Trials and “Sham” Surgery: Relevance to Modern Orthopaedics and Minimally Invasive Surgery. Iowa Orthop J. 26: 107–111.