The Problem with Placebos/Shams

This section was compiled by Frank M. Painter, D.C.
Make comments or suggestions to   Frankp@chiro.org

An Amusing Quote:

"A patient finally went to a chiropractor for her back pain after finding no relief with the orthopedist. After three adjustments and a week of no symptoms, she had a follow-up visit with her M.D.

Upon learning about the success of the D.C., the orthopedist stated, "That was just the placebo effect."

The patient responded, "If it works so well, why didn't you use it?"

–– Attributed to Robert Mootz, D.C.

Articles About Placebo Failures

	Avoiding Nocebo and Other Undesirable Effects in Chiropractic, Osteopathy and Physiotherapy: An Invitation to Reflect Musculoskelet Sci Pract 2022 (Oct 21); 62: 102677 ~ FULL TEXT This masterclass briefly introduces the nocebo effect and its underlying mechanisms. It then traces the historical development of chiropractic, osteopathy, and physiotherapy, arguing that there was and continues to be an excessive focus on the patient's body. Next, aspects of clinical practice, including communication, the therapeutic relationship, clinical rituals, and the wider social and economic context of practice are examined for their potential to generate nocebo and other undesirable effects. To aid reflection, a model to reflect on clinical practice and individual professions through the 'prism' of nocebo and other undesirable effects is introduced and illustrated. Finally, steps are proposed for how researchers, educators, and practitioners can maximise positive and minimise negative clinical context.
	Neurophysiological Mechanisms of Chiropractic Spinal Manipulation for Spine Pain European Journal of Pain 2021 (Mar 31); [EPUB] ~ FULL TEXT This narrative review highlights the most relevant mechanisms of pain relief by spinal manipulation and provides a perspective for future research on spinal manipulation and spine pain, including the validation of placebo interventions that control for placebo effects and other non-specific effects that may be induced by spinal manipulation.
	Context Matters: The Psychoneurobiological Determinants of Placebo, Nocebo and Context-related Effects in Physiotherapy Arch Physiother 2020 (Jun 11); 10: 11 ~ FULL TEXT Placebo and nocebo effects embody psychoneurobiological phenomena where behavioural, neurophysiological, perceptive and cognitive changes occur during the therapeutic encounter in the healthcare context. Placebo effects are produced by a positive healthcare context; while nocebo effects are consequences of negative healthcare context. Historically, placebo, nocebo and context-related effects were considered as confounding elements for clinicians and researchers. In the last two decades this attitude started to change, and the understanding of the value of these effects has increased. Despite the growing interest, the knowledge and the awareness of using the healthcare context to trigger placebo and nocebo effects is currently limited and heterogeneous among physiotherapists, reducing their translational value in the physiotherapy field.
	The Myth of the Placebo Response Frontiers in Pychiatry 2019 (Aug 16); 10: 577 ~ FULL TEXT Eliminating the myth of placebo will not be easy. Currently, medical care derived from the science of the small and particular provides us with only about 15–20% of the health benefits for populations, yet it gets 80–90% of the money. [48] Our inherent healing response as accessed through behavior and the social environment accounts for the other 80%. However, this approach to illness has no business model to drive it forward or make it accessible to everyone. Even more difficult than changing the economic model of healing will be changing our minds about how healing works. A good first step would be to see the placebo response for what it is — a conceptual myth that sustains a broken medical system and covers up what we are really seeking — our inherit healing capacity now freed by understanding how deeply meaning infuses us all.
	Implications of Placebo and Nocebo Effects for Clinical Practice: Expert Consensus Psychother Psychosom. 2018; 87 (4): 204–210 ~ FULL TEXT The current paper forms a first step towards developing evidence-based and ethical recommendations about the implications of placebo and nocebo research for medical practice, based on the current state of evidence and the consensus of experts. Future research might focus on how to implement these recommendations, including how to optimize conditions for educating patients about placebo and nocebo effects and providing training for the implementation in clinical practice.
	The Quality of Placebos used in Randomized, Controlled Trials of Lumbar and Pelvic Joint Thrust Manipulation - A Systematic Review Spine J. 2017 (Mar); 17 (3): 445–456 ~ FULL TEXT Twenty-five randomized, placebo-controlled trials were included in this review. There were 18 trials that used a sham manual SMT procedure for their placebo control intervention; the most common approach was with an SMT set-up, but without the application of any thrust. One small pilot study used an unequivocally indistinguishable placebo, 2 trials used placebos that had been validated as inert a priori, and 8 trials reported on success of subject blinding. Risk of bias was high or unclear, for all included studies.
	Different Placebos, Different Mechanisms, Different Outcomes: Lessons for Clinical Trials PLoS One. 2015 (Nov 4); 10 (11): e0140967 ~ FULL TEXT Clinical trials use placebos with the assumption that they are inert, thus all placebos are considered to be equal. Here we show that this assumption is wrong and that different placebo procedures are associated to different therapeutic rituals which, in turn, trigger different mechanisms and produce different therapeutic outcomes. We studied high altitude, or hypobaric hypoxia, headache, in which two different placebos were administered. The first was placebo oxygen inhaled through a mask, whereas the second was placebo aspirin swallowed with a pill.
	Validation of Placebo in a Manual Therapy Randomized Controlled Trial Sci Rep. 2015 (Jul 6); 5: 11774 ~ FULL TEXT At each treatment session, more than 80% of the participants believed that they had undergone active treatment, regardless of group allocation. The odds ratio for believing that active treatment was received was >10 for all treatment sessions in both groups (all p < 0.001). The blinding was maintained throughout the RCT. Our results strongly demonstrate that it is possible to conduct a single-blinded manual-therapy RCT with placebo and to maintain the blinding throughout 12 treatment sessions given over 3 months.
	Bad is More Powerful Than Good: The Nocebo Response in Medical Consultations Am J Med. 2015 (Feb); 128 (2): 126–129 ~ FULL TEXT Although there has been a lot of research looking at the placebo response, nocebo responses in the healthcare setting have been largely overlooked. This article explores the potential role of negative patient-doctor communication in facilitating nocebo responses in the medical consultation. We suggest that invalidation, that is, communicating a lack of understanding and acceptance to the patient (albeit unintentionally), is a key factor in understanding the nocebo response. This article reviews evidence from the experimental and healthcare setting, which suggests that the negative effects of invalidation may be stronger than we think.
	Manipulative Therapy: Just a Placebo? Dynamic Chiropractic (November 19, 2001) ~ FULL TEXT Chiropractic care, particularly spinal manipulation or adjustment, is an increasingly frequent topic in medicine and health care policy circles. As evidence has accumulated to support use of these services, there is frequent reference to a presumption of placebo effect being the mechanism of favorable responses reported in the literature. These charges are easily refuted by specific data. In my experience, a professional head-on response silences these critiques and allows the discussion to refocus on a much more useful topic: appropriate use the paragraphs that follow were crafted as a part of a book chapter on the role of chiropractic manipulation in management of pain the basis often used to set the stage for a claim of a placebo effect. An effective rejoinder follows.
	Placebo Effects In Trials Evaluating 12 Selected Minimally Invasive Interventions: A Systematic Review And Meta-Analysis BMJ Open. 2015 (Jan 30); 5 (1): e007331 ~ FULL TEXT It is normally assumed that medical practices are based on firm clinical evidence and that new practices or techniques are introduced when superiority, or at least non-inferiority, has been demonstrated compared to established treatments. However, medical history reveals numerous examples contradicting this assumption. Forty-two per cent of 146 medical practices were found to be reversed in a recent review analysing 10-years of publication in a high-impact medical journal. [1] Large effects of an intervention in initial reports are often spurious findings, while the vast majority may represent substantial overestimations. [2]
	The Magnitude of Nocebo Effects in Pain: A Meta-analysis Pain. 2014 (Aug); 155 (8): 1426–1434 ~ FULL TEXT This meta-analysis investigated nocebo effects in pain. Only studies that investigated nocebo effects as the effects that followed the administration of an inert treatment along with verbal suggestions of symptom worsening and that included a no-treatment control condition were eligible. Ten studies fulfilled the selection criteria. These findings are similar to those in the placebo literature. As the magnitude of the nocebo effect is variable and sometimes large, this meta-analysis demonstrates the importance of minimizing nocebo effects in clinical practice.
	Neurobiology of Placebo Effects: Expectations or Learning? Soc Cogn Affect Neurosci. 2014 (Jul); 9 (7): 1013–1021 ~ FULL TEXT The present work suggests that a priori expectations are not sufficient to explain the formation of placebo analgesic responses over a sustained period of time, exemplified here as a 20 min experimental pain model.   Using this model, we observed a lack of significant relationships between the level of expectations of pain relief and placebo-associated reductions in pain ratings. Using objective neurochemical measures acquired with PET, individuals with high expectations showed greater μ-opioid system activation in the DLPFC that were not associated with placebo analgesic effects.   These findings represent an apparent discrepancy with classical theories where the formation of placebo responses is dependent on the development of positive expectations.   Conversely, a learning mechanism defined by the discrepancy between expectations and subjectively rated effectiveness was associated with placebo analgesic responses, and with the activation of regional μ-opioid neurotransmission in a substantial number of regions implicated in opioid-mediated antinociception.
	The Power of the Placebo BrainFacts.org (May 31, 2012) ~ FULL TEXT As many as one in three patients report feeling better after receiving a drug that has no active ingredients. For decades, these findings — called the placebo effect — were dismissed as purely psychological. Now new research indicates that placebos can cause real biological changes, a finding that is transforming how medicine is practiced.
	Grasping The Placebo Effect: Different Strokes For Different Folks ChiroACCESS (1–03–2012) ~ FULL TEXT The popular American idiom, “Different strokes for different folks” is believed to have emerged from the American south in the 1950s [1] before it was practically immortalized as Sly & the Family Stone’s top-selling single recording about a decade later. [2] What is becoming more and more apparent, however, is that a new lease on life for that slogan has emerged--as evidence-based medicine becomes more and more cognizant of patient expectations and values as part of the evidence base.
	Nocebo is the Enemy, not Placebo. A Meta-analysis of Reported Side Effects After Placebo Treatment in Headaches Cephalalgia. 2011 (Apr); 31 (5): 550–561 ~ FULL TEXT In studies of symptomatic treatment for migraine, the nocebo and dropout frequencies were 18.45% and 0.33%, but rose to 42.78% and 4.75% in preventative treatment studies. In trials for prevention of TTH, nocebo and dropout frequencies were 23.99% and 5.44%. For symptomatic treatment of cluster headache, the nocebo frequency was 18.67%. Nocebo is prevalent in clinical trials for primary headaches, particularly in preventive treatment studies. Dropouts due to nocebo effect may confound the interpretation of many clinical trials.
	Placebo Response to Manual Therapy: Something Out of Nothing? J Man Manip Ther. 2011 (Feb); 19 (1): 11–19 ~ FULL TEXT Placebo is often considered an inert agent devoid of treatment effect. The more recent literature suggests, similar to manual therapy, that placebo has physiological and psychological effects on pain. We suggest that placebo is not ‘nothing’, but one of likely many potentially relevant mechanisms through which manual therapy improves clinical outcomes related to musculoskeletal pain conditions. We recommend that manual therapists take steps to maximize placebo responses within ethical limitations. We are not suggesting that manual therapists include ineffective or inert interventions in the care of their patients with the suggestion of likely positive responses. Rather, we recommend that manual therapists take steps to maximize placebo mechanisms through minimizing negative mood, maximizing realistic expectations, and drawing on patient preferences and past experience for evidence-based interventions.
	Imperfect Placebos Are Common In Low Back Pain Trials: A Systematic Review Of The Literature European Spine Journal 2008 (Jul); 17 (7): 889–904 ~ FULL TEXT This review reveals that imperfect placebos are common in low back pain trials, a finding that has implications for the design of future trials and also for the interpretation of published trials evaluating treatment of low back pain. Two common problems were identified in the design of trials: the use of placebos that are potentially not inert (as indicated by contemporary treatment) and the uncertain success of blinding.
	The Power of Context: Reconceptualizing the Placebo Effect J R Soc Med. 2008 (May); 101 (5): 222–225 ~ FULL TEXT Scientific interest in the placebo effect has grown dramatically over the past thirty years. For the three decades from 1977 to 2006, the number of citations listed on PubMed for ‘the placebo effect’ has increased from 214 to 651 to 1675. Writing in 1984, Jay Katz noted that ‘Physicians and patients may gradually learn that the placebo effect is an integral and inevitable component of the practice of medicine, that it constitutes its art and augments its science.’ [1] Despite increasing scientific attention to the placebo effect, including extensive experimentation aimed at understanding the mechanisms underlying this phenomenon, Katz's prediction has yet to be realized. Apart from purely scientific interest in the neurobiology of the placebo effect, the leading rationale for research on this phenomenon is to harness the presumed power of the placebo effect to enhance therapeutic outcomes in clinical practice. A major barrier to clinical translation of the substantial investment in laboratory experimentation on the placebo effect is the confusing and misleading way in which this phenomenon is conceived.
	Understanding and Promoting Placebo Effects The Chiropractic Report (January 2008) ~ FULL TEXT For every patient seeking health care there are three fundamental sources of healing: The natural healing powers of the body – so often underestimated and undermined by patients and their health care professionals, and of central importance to the philosophy and good practice of chiropractic. The specific effects of treatment The placebo or non-specific effects of the treatment and whole health care encounter with the health professional chosen by the patient. Accordingly, good clinical practice by any health care professional should promote all three sources of healing.
	A Randomized Trial Investigating a Chiropractic Manual Placebo: A Novel Design Using Standardized Forces in the Delivery of Active and Control Treatments J Altern Complement Med 2005 (Feb); 11 (1): 109–117 Patients in the control group were not successfully blinded; however, patients' perceptions of treatment group assignment did not significantly affect outcomes. The clinically significant improvement in both groups, independent of patient or clinician expectations, suggests the presence of therapeutic factors common to both groups, other than biomechanical force. Further studies examining other aspects of the clinical encounter, considered separately from biomechanical force, are warranted before arbitrarily designating any intervention as a placebo.
	The Placebo, the Sensory Trick and Chiropractic Chiropractic Journal of Australia 2004 (Jun); 34 (2): 58–62 ~ FULL TEXT Stimuli used as placebo procedures in recent chiropractic clinical trials are quite similar, in terms of site and modality, to the "sensory tricks" that either cause substantial temporary relief, or, alternatively, provocation of symptoms in dystonic patients. Caution should be used in assuming that control (placebo) procedures used in chiropractic clinical trials lack specific effects on neuromusculoskeletal symptomatology.
	Fables or Foibles: Inherent Problems with RCTs J Manipulative Physiol Ther 2003 (Sept); 26 (7): 460 ~ FULL TEXT The 7 case studies reviewed in this report combined with an emerging concept in the medical literature both suggest that reviews of clinical research should accommodate our increased recognition of the values of cohort studies and case series. The alternative would have been to assume categorically that observational studies rather than RCTs provide inferior guidance to clinical decision-making. From this discussion, it is apparent that a well-crafted cohort study or case series may be of greater informative value than a flawed or corrupted RCT. To assume that the entire range of clinical treatment for any modality has been successfully captured by the precision of analytical methods in the scientific literature, indicates Horwitz, would be tantamount to claiming that a medical librarian who has access to systematic reviews, meta-analyses, Medline, and practice guidelines provides the same quality of health care as an experienced physician.
	Osteopathic Manipulation No Better Than Sham Therapy for Chronic Back Pain? Spine (Phila Pa 1976) 2003 (Jul); 28 (13): 1355–1362 Here's another study with the unusual finding that the sham and the active treatment groups both fared similarly...that is, both groups improved, compared to the control group. It would be interesting to know the exact nature of the sham they were using. The Placebo Page is devoted to this issue...the difficulty in designing a truly inert sham or placebo for a manipulative trial.
	Pondering the Placebo Effect Newsweek (December 2, 2002) ~ FULL TEXT Whether you regard it as an annoyance or a miracle, you have to marvel at the power of suggestion. When doctors test a new medical treatment, they conclude that it works only when patients who receive it fare significantly better than those given a fake treatment, or placebo. That’s because many people feel better no matter which one they receive.
	The Placebo Effect in Alternative Medicine: Can the Performance of a Healing Ritual Have Clinical Significance? Annals of Internal Medicine 2002 (Jun 4); 136 (11): 817–825 ~ FULL TEXT Five components of the placebo effect — patient, practitioner, patient-practitioner interaction, nature of the illness, and treatment and setting — are examined. Therapeutic patterns that heighten placebo effects are especially prominent in unconventional healing, and it seems possible that the unique drama of this realm may have "enhanced" placebo effects in particular conditions. Ultimately, only prospective trials directly comparing the placebo effects of unconventional and mainstream medicine can provide reliable evidence to support such claims. Nonetheless, the possibility of enhanced placebo effects raises complex conundrums. Can an alternative ritual with only nonspecific psychosocial effects have more positive health outcomes than a proven, specific conventional treatment? What makes therapy legitimate, positive clinical outcomes or culturally acceptable methods of attainment? Who decides?
	Deconstructing the Placebo Effect and Finding the Meaning Response Annals of Internal Medicine 2002 (Mar 19); 136 (6): 471–476 ~ FULL TEXT We provide a new perspective with which to understand what for a half century has been known as the "placebo effect." We argue that, as currently used, the concept includes much that has nothing to do with placebos, confusing the most interesting and important aspects of the phenomenon. We propose a new way to understand those aspects of medical care, plus a broad range of additional human experiences, by focusing on the idea of "meaning," to which people, when they are sick, often respond. We review several of the many areas in medicine in which meaning affects illness or healing and introduce the idea of the "meaning response." We suggest that use of this formulation, rather than the fixation on inert placebos, will probably lead to far greater insight into how treatment works and perhaps to real improvements in human well-being.
	Issues in Planning a Placebo-controlled Trial of Manual Methods: Results of a Pilot Study J Altern Complement Med 2002 (Feb); 8 (1): 21–32 ~ FULL TEXT The technical and personnel resources required to achieve adequate standardization of procedures at multiple sites may make a placebo-controlled trial unfeasible, given our current lack of knowledge about the active agent in manual chiropractic procedures.

Please note that the following 4 articles require the free Adobe Acrobat (PDF) Reader to download these FULL TEXT articles.   Thanks to J Alternative and Complementary Medicine for providing access to them!

	Methodological Changes in the Evaluation of Complementary and Alternative Medicine: Issues Raised by Sherman et al. and Hawk et al.   (PDF) J Altern Complement Med 2002 (Feb); 8 (1): 11–19 ~ FULL TEXT The quest for methodologies appropriate for evaluating complementary and alternative medicine (CAM) continues to challenge the research community. Two papers in this issue (See below) demonstrate efforts by thoughtful investigators to develop legitimate placebo interventions and to address standardization of delivery.
	Description and Validation of a Noninvasive Placebo Acupuncture Procedure   (PDF) J Altern Complement Med 2002 (Feb); 8 (1): 11–19 ~ FULL TEXT In the first experiment, the toothpick insertions were perceived as slightly more like real needling than the real needling (mean ratings of 2.8 and 2.1, respectively; p = 0.08). In the second experiment, 52% percent of those receiving the simulated needling versus 63% of those receiving real acupuncture believed they were "definitely" or "probably" receiving real acupuncture (p = 0.33).
	Issues in Planning a Placebo-Controlled Trial of Manual Methods: Results of a Pilot Study   (PDF) J Altern Complement Med 2002 (Feb); 8 (1): 21–32 ~ FULL TEXT The technical and personnel resources required to achieve adequate standardization of procedures at multiple sites may make a placebo-controlled trial unfeasible, given our current lack of knowledge about the active agent in manual chiropractic procedures.
	The Efficacy Paradox in Randomized Controlled Trials of CAM and Elsewhere: Beware of the Placebo Trap   (PDF) J Altern Complement Med 2001 (Jun); 7 (3): 213–218 ~ FULL TEXT Ever since it's formal inauguration in 1945, the double-blind, randomized controlled trial (RTC) has become the "Holy Grail" of medical methodology. This is understandable because the RTC has an advantage that the other methods are lacking: it – ideally – precludes bias.

End of Adobe Acrobat (PDF) articles

	COMMENTS ON: Chronic Pediatric Asthma and Chiropractic Spinal Manipulation: A Prospective Clinical Series and Randomized Clinical Pilot Study J Manipulative Physiol Ther 2002 (Oct); 25 (8): 540–541 ~ FULL TEXT One obvious problem in this study that is common to studies of physical-type treatments in general is an inadequate placebo treatment in the control or sham group. It is not inadequate in the classical sense of lacking a control group but inadequate in the sense that the sham control may be introducing a second active treatment in the supposed inert placebo intervention. The sham procedure used in this study requires some questionable assumptions.
	Placebo Surgery Chiropractic Journal 2002 (Sep) ~ FULL TEXT Many scientists and clinicians consider the placebo-controlled trial the "gold standard" for evidence-based practice. Interestingly, surgical procedures are often exempt from such scrutiny. Ethical considerations are considered barriers to the use of placebo-controlled investigations for surgical procedures. [3,4] Interestingly, there have been five studies where placebo surgery was used as a control. The placebo group generally did as well or better than the group receiving the real operation.
	Placebo Surgery Gains Wider Acceptance New York (MedscapeWire) (Mar 23, 2002) The ethical dilemma surrounding placebo surgery has been eclipsed by the controversial use — and failure — of stem cell therapy in 2 Parkinson's disease (PD) studies. News of the most recent setback in PD research was released on March 16 when the Genzyme Corporation and Diacrin Inc. reported that in preliminary results from phase 2 clinical trials, no significant improvement resulted from implanting the fetal cells of pigs into patient brains when compared with subjects who received placebo surgery.
	Placebo and Placebo Effects - A Review Psychother Psychosom Med Psychol 2002 (Aug); 52 (8): 332–342 Placebo controls in clinical trials are usually employed to filter out undesired, psychological or non-specific effects from "true" therapeutic effects. Although this is useful in the context of clinical trials for the purpose of proving pharmacological efficacy, it is misleading to generalize this strategy to therapy as a whole. This would imply that placebo effects are irrelevant.
	A Controlled Trial of Arthroscopic Surgery for Osteoarthritis of the Knee New England Journal of Medicine 2002 (Jul 11); 347 (2): 81–88 ~ FULL TEXT In this controlled trial of arthroscopic surgery for osteoarthritis of the knee, a total of 180 patients with osteoarthritis of the knee were randomly assigned to receive arthroscopic debridement, arthroscopic lavage, or placebo surgery. Pain and function were assessed over a 24-month period. The result? "At no point did either of the intervention groups report less pain or better function than the placebo group." This investigation followed a smaller pilot study with similar results. [10] You may also enjoy this byline: Does Knee Surgery Actually Help?.
	The Nocebo Effect: Placebo's Evil Twin The Washington Post (April 30, 2002) ~ FULL TEXT Fifteen years ago, researchers at three medical centers undertook a study of aspirin and another blood thinner in heart patients and came up with an unexpected result that said little about the heart and much about the brain. At two locations, patients were warned of possible gastrointestinal problems, one of the most common side effects of repeated use of aspirin. At the other location, patients received no such caution. When researchers reviewed the data, they found a striking result: Those warned about the gastrointestinal problems were almost three times as likely to have the side effect. Though the evidence of actual stomach damage such as ulcers was the same for all three groups, those with the most information about the prospect of minor problems were the most likely to experience the pain.
	Manual Medicine Diversity: Research Pitfalls and the Emerging Medical Paradigm J Am Osteopath Assoc 2001 (Aug); 101 (8): 441–444 ~ FULL TEXT Recent studies published in leading medical journals have concluded that chiropractic treatment is not particularly helpful for relieving asthma and migraine symptoms because even though study participants showed notable improvement in symptoms, those subjects who received sham manual medicine treatments also showed improvement. Yet the sham treatment received by control groups in these studies is reminiscent in many ways of traditional osteopathic manipulation. This seems to represent not only a failure to recognize the value of many manual medicine techniques but also an ignorance of the broad spectrum of manual medicine techniques used by various practitioners, from osteopathic physicians to chiropractors to physical therapists.
	Is the Placebo Powerless? — An Analysis of Clinical Trials Comparing Placebo with No Treatment New England Journal of Medicine 2001 (May 24); 344 (21): 594–1602 ~ FULL TEXT In conclusion, we found little evidence that placebos in general have powerful clinical effects. Placebos had no significant pooled effect on subjective or objective binary or continuous objective outcomes. We found significant effects of placebo on continuous subjective outcomes and for the treatment of pain but also bias related to larger effects in small trials. The use of placebo outside the aegis of a controlled, properly designed clinical trial cannot be recommended.
	Debunking the Placebo Effect Nutrition Science News (March 2001) ~ FULL TEXT Any beneficial effect derived from natural remedies such as vitamins, minerals and herbs is often discounted as being nothing more than the consumer's belief that they will work. With an air of authority, skeptics claim that natural medicine is quackery, effective only because of the placebo effect. In 1955, Henry K. Beecher, M.D., was the first to report on the so-called placebo effect. Beecher claimed that about 35 percent of the time, patients who took a pill containing no active ingredients experienced an improvement in their condition. In 1997, researchers at the Institute for Applied Theory and Methodologies in Health Care, in Frieburg, Germany, decided to look into Beecher's theory. Reporting in the Journal of Clinical Epidemiology, they scrutinized the 15 different clinical studies cited by Beecher. Here is what they found.
	Use of a Pilot to Refine the Design of a Study to Develop a Manual Placebo Treatment J Neuromusculoskeletal System 2000 (Summer); 8 (2): 39–48 Development of an appropriate placebo treatment is one of the major challenges in designing chiropractic clinical trials. To date, such trials have not provided convincing eveidence that both 1) the manual placebo did in fact act as a placebo, and 2) patients were successfully blinded to treatment group assignment. In order to develop a manual placebo treatment that will satisfy these criteria, the authors first conducted a pilot study with a 2x2 factorial design to assess recruitment and study protocols and refine the study design.
	The Placebo Prescription New York Times Magazine (Jan 9, 2000) ~ FULL TEXT An interesting article posits the question: "How did (the arthroscopic surgeon) know that whatever benefit came from this surgery wasn't a product of the placebo effect -- that is, that those who improved did so, not because the operation actually healed the knee joint, but because (the patient) expected it would?"   Fascinating reading, and may be applied to the chiropractic intervention as well.
	A Randomized, Placebo-controlled Clinical Trial on the Efficacy of Chiropractic Therapy on Premenstrual Syndrome J Manipulative Physiol Ther 1999 (Nov); 22 (9): 582–585 ~ FULL TEXT Within the limitations of the study, the results support the hypothesis that the symptoms associated with PMS can generally be reduced by chiropractic treatment consisting of adjustments and soft-tissue therapy. However, the role of a placebo effect needs further elucidation, given that the group receiving the placebo first, although improving over the baseline, showed no further improvement when they had actual treatment.
	Preliminary Study of the Effects of a Placebo Chiropractic Treatment with Sham Adjustments J Manipulative Physiol Ther 1999 (Sep); 22 (7): 436–443 ~ FULL TEXT Although VAS and GWBS scores improved with both treatments, a somewhat greater improvement occurred in most cases with the active treatment. Eight of 14 patients interviewed believed that the placebo had a treatment effect.
	The Powerful Placebo: From Ancient Priest to Modern Physician British Medical Journal 1998 (May 2); 316: 1396 ~ FULL TEXT "Placebo" formerly encompassed both drug and non-drug treatments of disease, but with the proliferation of controlled treatment trials since the 1950s the term has come to mean an "inert" substance or procedure used as a control in bioscience experiments, in particular clinical drug trials. The psychiatrist authors plead for a re-widening of the concept to cover all treatments, including psychotherapy. They define placebo as "any treatment, or component thereof, which is knowingly used for its non-specific physiological or psychophysiological therapeutic effect, but is without specific activity."
	The Placebo Effect: Can Ee Use It Better? British Medical Journal 1994 (Jul 9); 309 (6947): 69–70 ~ FULL TEXT Placebos work best for pain, disorders of autonomic sensation, and disorders of factors under neurohumoral control. Shapiro defined a placebo as any treatment deliberately used for non-specific psychological or psychophysiological effect. [1] That the placeo effect, a classic example of the mind-body relation, is as clinically undeveloped as it is pervasive may reflect the dominance of modern chemotherapy. The placebo depends on largely subconscious interactions between the doctor, the treatment process, and the patient [1, 2]; it is the form of a treatment without its substance.

Possible Solutions ???

	Validation of a Novel Sham Cervical Manipulation Procedure Spine J. 2012 (Nov); 12 (11): 1021–1028 ~ FULL TEXT The novel sham procedure has been shown to be effective in masking subjects to group allocation and to be clinically inert with respect to common outcomes in the immediate posttreatment stage. Further research on serial applications and for multiple operators is warranted.
	A True Blind for Subjects Who Receive Spinal Manipulation Therapy Arch Phys Med Rehabil 2009 (Feb); 90 (2): 366–368 ~ FULL TEXT In each subject, propofol and remifentanil were administered intravenously. Once unconsciousness was achieved (3–5min), subjects were placed in a lateral recumbent position and then randomized to either a control group (n=3) or an experimental group (with SMT, n=3); subjects received a single SMT to the lumbar spine. Subjects were given a standardized auditory and visual cue and then allowed to recover from anesthesia in a supine position (3–5min). In either the experimental or control group, subjects could not recall any event while under anesthesia. Some SMT subjects reported pain reduction greater than the minimally important clinical difference and greater than control subjects. No adverse events were reported.
	Validation of a Sham Manipulative Procedure for the Cervical Spine for Use in Clinical Trials J Manipulative Physiol Ther 2005 (Nov); 28 (9): 662–666 ~ FULL TEXT The sham cervical manipulation studied here appears to approximate the necessary features of a placebo maneuver in that it is perceived by a majority of nonstudent neck pain subjects to be a real manipulation, although it does not produce any important change in cervical status. The small sample size of nonstudent participants precludes a strong recommendation for this procedure at this time.

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