Homeopaths have, since about 200 years, insisted that their remedies are efficacious treatments for infectious diseases. As evidence for this notion, they often produce epidemiological data showing that a group of infected patients treated homeopathically had better results than another group treated conventionally. While potentially interesting, such findings never constitute proof, because the two groups might not have been comparable and many other factors could have determined the observed outcome. In fact, these stories are prime examples for the need of rigorously controlled trials when testing the efficacy of medical treatments.

Homeopaths are invariably unable to provide more compelling evidence for their claims. Instead, they repeat, since 200 years, their assumptions over and over again. Are they not aware, I ask myself, that the repetition of a lie does not create a truth?

What their repetition of lies sometimes does create, unfortunately, is some impact on a political level. This website explains it fairly well:

The Public Health Ministry (of Thailand) is thinking of implementing alternative therapy homeopathy in all districts of Sing Buri this year, after a report that it could boost the human’s body immunity to fight dengue fever, an inspector-general at the ministry said.

Homeopathic medicines had been given to Sing Buri volunteer students from kindergarten to lower-secondary level in a 2012-13 trial and it yielded satisfactory results, said Dr Jakkriss Bhumisawasdi, director of the Inspector-General Region for Bureau of Inspection and Evaluation.

The number of dengue fever cases in Sing Buri have gone down, taking its rankings from No 67 in the country (with one death) in 2011 to No 76 in 2012. As there was a nationwide dengue fever outbreak in 2013, Sing Buri reported the country’s lowest prevalence at 44.95 per 100,000 population.

Jakkriss said “homeopathy” was safe and low-cost and had been used in various countries including the United Kingdom, France, Italy, Switzerland, Belgium, the United States, Australia, India and Malaysia.

Pilot project

Next, the system of medicine would be implemented in Region 4 Bureau’s seven other provinces: Nakhon Nayok, Nonthaburi, Pathum Thani, Ayutthaya, Lop Buri, Sara Buri and Ang Thong. If this one district per province pilot project went well, they would consider implementing it across the country, he said.

Sing Buri Hospital paediatrician Dr Wali Suwatthika said the preparation involved dissolving Eupatorium herbal pills in drinking water. Each child would be given 3cc of this tasteless water every three months. The trial, which began in July 2012, covered 4,250 children in Muang district and only four of them developed mild dengue fever in one year, while seven out of the district’s 2,856 remaining kids who didn’t get the medicine had dengue fever, in a more severe condition.

Thailand reported 150,934 dengue fever patients last year, double the previous year’s number, and 133 deaths. As there is no vaccine for dengue fever, the Public Health Ministry used a combination of several measures, including the eradication of mosquito larva incubation grounds and a campaign for people to install mosquito nets.


So, where is the evidence that homeopathy does anything at all for Dengue patients? The 2012-13 trial referred to above has, as far as I can see, not been published. This probably means that it was not a publishable study at all. The only study available on Medline is this one:

A double-blind, placebo-controlled randomized trial of a homeopathic combination medication for dengue fever was carried out in municipal health clinics in Honduras. Sixty patients who met the case definition of dengue (fever plus two ancillary symptoms) were randomized to receive the homeopathic medication or placebo for 1 week, along with standard conventional analgesic treatment for dengue. The results showed no difference in outcomes between the two groups, including the number of days of fever and pain as well as analgesic use and complication rates. Only three subjects had laboratory confirmed dengue. An interesting sinusoidal curve in reported pain scores was seen in the verum group that might suggest a homeopathic aggravation or a proving. The small sample size makes conclusions difficult, but the results of this study do not suggest that this combination homeopathic remedy is effective for the symptoms that are characteristic of dengue fever.


The bottom line is simple and depressing: the totality of the best available evidence fails to show that homeopathy is efficacious for Dengue fever (or any other infectious disease). It is irresponsible to claim otherwise.

If you want to scientifically investigate this question, it might be a good idea NOT to start with the following sentence: “Auricular acupuncture (AA) is effective in the treatment of preoperative anxiety”. Yet, this is exactly what the authors did in their recent publication.

The aim of this new study was to investigate whether AA can reduce exam anxiety as compared to placebo and no intervention. Forty-four medical students were randomized to receive AA, placebo, or no intervention in a crossover manner. Subsequently they completed three comparable oral anatomy exams with an interval of one month between the exams/interventions.

A licensed acupuncturist with more than five years of experience with this technique applied AA at the acupuncture points MA-IC1 (Lung), MA-TF1 (ear Shenmen), MA-SC (Kidney), MA-AT1 (Subcortex) and MA-TG (Adrenal gland) bilaterally. Indwelling fixed ‘New Pyonex’ needles embedded in a skin-coloured adhesive tape were used for AA. The participants were instructed by the acupuncturist to stimulate the auricular needles for 3–5 minutes, if they felt anxious. For the placebo procedure, ‘New Pyonex’ placebo needles were attached to five sites on the helix of the auricle bilaterally. ‘New Pyonex’ placebo needles have the same appearance as AA needles but consist of self-adhesive tape only. In order to avoid potential physiologic effects of acupressure, the participants were not instructed to stimulate the attached ‘New Pyonex’ placebo needles. AA and placebo needles were left in situ until the next day and were removed out of sight of the participants after the exam by the investigator, who was not involved in acupuncture procedure

Levels of anxiety were measured using a visual analogue scale before and after each intervention as well as before each exam. Additional measures included the State-Trait-Anxiety Inventory, duration of sleep at night, blood pressure, heart rate and the extent of participant blinding.

All included participants finished the study. Anxiety levels were reduced after AA and placebo intervention compared to baseline and the no intervention condition (p < 0.003). Moreover, AA was also better at reducing anxiety than placebo in the evening before the exam (p = 0.018). Participants were able to distinguish between AA and placebo intervention.

The authors concluded that both auricular acupuncture and placebo procedure were shown to be effective in reducing levels of exam anxiety in medical students. The superiority of verum AA over placebo AA and no intervention is considered to be due to stimulation of cranial nerves, but may have been increased in effect by insufficient participant blinding.

Here are just three of the major concerns I have about this study:

  • The trial design seems odd: a crossover study can only work well, if there is a stable baseline. This may not be the case with three consecutive exams; the anxiety experienced by students is bound to get less as time goes by. I think anyone who has passed a series of exams will confirm that there is a large degree of habituation.
  • It seems inadequate to employ just one acupuncturist; it means that the trial might end up testing not acupuncture per se but the skills of the therapist.
  • The placebo used for this study cannot possibly have fooled anyone into believing that it was real AA; volunteers were not even instructed to ‘stimulate’ the placebo devices. The difference to the ‘real thing’ must have been very clear to all involved. This means that the control for placebo-effects was woefully incomplete. In turn, this means that the observed outcomes are most likely due to residual bias.

In view of these concerns, allow me to re-phrase the authors’ conclusions:


This meta-analysis was performed “to ascertain the effectiveness of oral aloe vera consumption on the reduction of fasting blood glucose (FBG) and hemoglobin A1c (HbA1c).”

PubMed, CINAHL, Natural Medicines Comprehensive Database, and Natural Standard databases were searched. The searches were limited to clinical trials or observational studies conducted in humans and published in English. Studies of aloe vera’s effect on FBG, HbA1c, homeostasis model assessment-estimated insulin resistance (HOMA-IR), fasting serum insulin, fructosamine, and oral glucose tolerance test (OGTT) in prediabetic and diabetic populations were examined.

Nine studies were included in the FBG parameter (n = 283); 5 of these studies included HbA1c data (n = 89). Aloe vera decreased FBG by 46.6 mg/dL (p < 0.0001) and HbA1c by 1.05% (p = 0.004). Significant reductions of both endpoints were maintained in all subgroup analyses. Additionally, the data suggested that patients with an FBG ≥200 mg/dL may see a greater benefit. A mean FBG reduction of 109.9 mg/dL was observed in this population (p ≤ 0.0001). There was evidence of publication bias with FBG but not with HbA1c.

The authors concluded that the results of this meta-analysis support the use of oral aloe vera for significantly reducing both FBG (46.6 mg/dL) and HbA1c (1.05%) in prediabetic and diabetic patients. However, given the current overall quality and relative scarcity of data, further clinical studies that are more robust and better controlled are warranted to confirm and further explore these findings.

Oh no, the results do not support the use of aloe vera at all!!


Because this ‘meta-analysis’ is of unacceptably poor quality. Here are just some of the flaws that render it totally useless, particularly for issuing advice such as above:

  • The authors included uncontrolled observational studies which make no attempt to control for non-specific effects.
  • In several studies, the use of concomitant anti-diabetic medications was allowed; therefore it is not possible to establish cause and effect by aloe vera.
  • The search strategy was woefully inadequate; for instance non-English publications were not considered.
  • There was no assessment of the scientific rigor of the included studies; this totally invalidates the reliably of the conclusions.
  • The included studies used preparations of widely different aloe vera preparations, and there is no way of knowing the does of the active ingredients.

Diabetes is a serious condition that affects millions worldwide. If some of these patients are sufficiently gullible to follow the conclusions of this paper, they might be dead within a matter of days. This makes this article one of the most dangerous papers that I have seen in the ‘peer-reviewed’ literature of alternative medicine.

Who publishes such utter and irresponsible rubbish?

You may well ask.

The journal has been discussed on this blog  before for the junk that regularly appears in its pages, and so has its editor in chief. The authors (and the reviewers) are not known to me, but one thing is for sure: they don’t know the first thing about conducting a decent systematic review/meta-analysis.

The common cold is one of the indications for which homeopathy is deemed to be effective… by homeopaths that is! Non-homeopaths are understandably critical about this claim, not least because there is no good evidence for it. But, hold on, there is a new study which might change all this.

This study was recently published in COMPLEMENTARY THERAPIES IN MEDICINE which is supposed to be one of the better journals in this area. According to its authors, it was conducted “to determine if a homeopathic syrup was effective in treating cold symptoms in preschool children.” Children diagnosed with an upper respiratory tract infection were randomized to receive a commercial homeopathic cold syrup containing allium cepa 6X, hepar sulf calc 12X, natrum muriaticum 6X, phosphorous 12X, pulsatilla 6X, sulphur 12X, and hydrastasis 6X or placebo. Parents administered the study medication as needed for 3 days. The primary outcome was change in symptoms one hour after each dose. Parents also assessed the severity of each of the symptoms of runny nose, cough, congestion and sneezing at baseline and twice daily for 3 days, using a 4-point rating scale. A composite cold score was calculated by combining the values for each of the four symptoms. Among 261 eligible participants, data on 957 doses of study medication in 154 children were analyzed. There was no significant difference in improvement one hour after the dose for any symptom between the two groups. Analysis of twice daily data on the severity of cold symptoms compared to baseline values found that improvements in sneezing, cough and the composite cold score were significantly greater at both the first and second assessments among those receiving the cold syrup compared to placebo recipients.

The authors concluded that the homeopathic syrup appeared to be effective in reducing the severity of cold symptoms in the first day after beginning treatment.

Where to start? There are so many problems with this study that I find it difficult to chose the most crucial ones:

  • The study had a clearly defined primary endpoint; it was not affected by the homeopathic treatment which doubtlessly makes the study a negative trial. The only correct conclusion therefore is that THE HOMEOPATHIC SYRUP FAILED TO AFFECT THE PRIMARY OUTCOME MEASURE OF THIS STUDY. THEREFORE THE TRIAL DID NOT PRODUCE ANY EVIDENCE TO ASSUME THAT THE EXPERIMENTAL TREATMENT WAS EFFICACIOUS.
  • I don’t think that many of the primary or secondary outcome measures are validated or reliable.
  • All the positive results reported in the abstract and the article relate to secondary endpoints which are purely explanatory by nature. They should, in my view, not be mentioned in the conclusions at all.
  • The fact that some results turned out to be positive can be explained by the fact that the investigators ran dozens of tests for statistical significance which means that, by simple chance, some will turn out to produce a positive result.
  • A further explanation for the seemingly positive results might be the fact disclosed in the text of the article that the children in the homeopathy group received more conventional drugs than those in the placebo group.
  • Whatever the reason for these positive results, they certainly had nothing to do with the homeopathic syrup.
  • The study was funded by the company producing the syrup and for which one of the authors was employed as a consultant. This might be an explanation for the abominably poor science. In other words, this paper is not an exercise in testing a hypothesis but one in marketing.

While I might forgive the company for trying to maximise their sales figures, I do find it harder to forgive the authors, reviewers and editors for publishing such overtly false conclusions. In my view, they are all guilty of scientific misconduct.

Meniscus-injuries are common and there is no consensus as to how best treat them. Physiotherapists tend to advocate exercise, while surgeons tend to advise surgery.

Of course, exercise is not a typical alternative therapy but, as many alternative practitioners might disagree with this statement because they regularly recommend it to their patients, it makes sense to cover it on this blog. So, is exercise better than surgery for meniscus-problems?

The aim of this recent Norwegian study aimed to shed some light on this question. Specifically wanted to determine whether  exercise therapy is superior to arthroscopic partial meniscectomy for knee function in  patients with degenerative meniscal tears.

A total of 140 adults with degenerative medial meniscal tear verified by magnetic resonance imaging were randomised to either receiving 12 week supervised exercise therapy alone, or arthroscopic partial meniscectomy alone. Intention to treat analysis of between group difference in change in knee injury and osteoarthritis outcome score (KOOS4), defined a priori as the mean score for four of five KOOS subscale scores (pain, other symptoms, function in sport and recreation, and knee related quality of life) from baseline to two-year follow-up and change in thigh muscle strength from baseline to three months.

The results showed no clinically relevant difference between the two groups in change in KOOS4 at two years (0.9 points, 95% confidence interval −4.3 to 6.1; P=0.72). At three months, muscle strength had improved in the exercise group (P≤0.004). No serious adverse events occurred in either group during the two-year follow-up. 19% of the participants allocated to exercise therapy crossed over to surgery during the two-year follow-up, with no additional benefit.

The authors concluded that the observed difference in treatment effect was minute after two years of follow-up, and the trial’s inferential uncertainty was sufficiently small to exclude clinically relevant differences. Exercise therapy showed positive effects over surgery in improving thigh muscle strength, at least in the short-term. Our results should encourage clinicians and middle-aged patients with degenerative meniscal tear and no definitive radiographic evidence of osteoarthritis to consider supervised exercise therapy as a treatment option.

As I stated above, I mention this trial because exercise might be considered by some as an alternative therapy. The main reason for including it is, however, that it is in many ways an exemplary good study from which researchers in alternative medicine could learn.

Like so many alternative therapies, exercise is a treatment for which placebo-controlled studies are difficult, if not impossible. But that does not mean that rigorous tests of its value are impossible. The present study shows the way how it can be done.

Meaningful clinical research is no rocket science; it merely needs well-trained scientists who are willing to test the (rather than promote) their hypotheses. Sadly such individuals are as rare as gold dust in the realm of alternative medicine.

WHAT DOCTORS DON’T TELL YOU (WDDTY) is probably the most vile publication I know. It systematically misleads its readers by alarming news about this or that conventional treatment, while relentlessly promoting pseudoscientific non-sense. This article , entitled “MMR can cause skin problems and ulcers if your immune system is compromised” is a good example (one of a multitude):

The MMR vaccine can cause serious adverse reactions, researchers have admitted this week. The rubella (German measles) component of the jab increases the risk of infection from the rubella virus itself, and can cause serious skin inflammation and ulcers in anyone whose immune system is compromised.

The risk is highest among people with primary immunodeficiency diseases (PIDD), chronic genetic disorders that cause the immune system to malfunction.

Although the risk for people with compromised immune systems has been known, and is even included in the package inserts supplied with the vaccine, it was theoretical, say researchers from the Children’s Hospital of Philadelphia, who say they have uncovered “genuine evidence of harm.”

The researchers analysed the health profile of 14 people—four adults and 10 children—who suffered some form of a PIDD. Seven of them still had the rubella virus in their tissues, suggesting that their immune systems were too weak to get rid of the virus in the vaccine. The virus can damage skin cells and cause ulcers, and makes the person more susceptible to the actual rubella virus, the researchers say.

People with a poor immune system already have compromised T-cells—which are responsible for clearing viral infections—and the MMR makes the problem worse.


And what is wrong with this article?

The answer is quite a lot:

  1. The research seems to be about a very specific and rare condition, yet WDDTY seem to want to draw much more general conclusions.
  2. The research itself is not described in a way that it would be possible to evaluate.
  3. The sample size of what seems to have been a case-control study was tiny.
  4. The study is not properly cited for the reader to verify and check; for all we know, it might not even exist.
  5. I was not able to find the publication on Medline, based on the information given.

Collectively, these points render the article not just useless, in my view, but make it a prime example of unethical, unhelpful and irresponsible scaremongering.


Acupuncture for hot flushes?

What next?

I know, to rational thinkers this sounds bizarre – but, actually, there are quite a few studies on the subject. Enough evidence for me to have published not one but four different systematic reviews on the subject.

The first (2009) concluded that “the evidence is not convincing to suggest acupuncture is an effective treatment of hot flash in patients with breast cancer. Further research is required to investigate whether there are specific effects of acupuncture for treating hot flash in patients with breast cancer.”

The second (also 2009) concluded that “sham-controlled RCTs fail to show specific effects of acupuncture for control of menopausal hot flushes. More rigorous research seems warranted.”

The third (again 2009) concluded that “the evidence is not convincing to suggest acupuncture is an effective treatment for hot flush in patients with prostate cancer. Further research is required to investigate whether acupuncture has hot-flush-specific effects.”

The fourth (2013), a Cochrane review, “found insufficient evidence to determine whether acupuncture is effective for controlling menopausal vasomotor symptoms. When we compared acupuncture with sham acupuncture, there was no evidence of a significant difference in their effect on menopausal vasomotor symptoms. When we compared acupuncture with no treatment there appeared to be a benefit from acupuncture, but acupuncture appeared to be less effective than HT. These findings should be treated with great caution as the evidence was low or very low quality and the studies comparing acupuncture versus no treatment or HT were not controlled with sham acupuncture or placebo HT. Data on adverse effects were lacking.”

And now, there is a new systematic review; its aim was to evaluate the effectiveness of acupuncture for treatment of hot flash in women with breast cancer. The searches identified 12 relevant articles for inclusion. The meta-analysis without any subgroup or moderator failed to show favorable effects of acupuncture on reducing the frequency of hot flashes after intervention (n = 680, SMD = − 0.478, 95 % CI −0.397 to 0.241, P = 0.632) but exhibited marked heterogeneity of the results (Q value = 83.200, P = 0.000, I^2 = 83.17, τ^2 = 0.310). The authors concluded that “the meta-analysis used had contradictory results and yielded no convincing evidence to suggest that acupuncture was an effective treatment of hot flash in patients with breast cancer. Multi-central studies including large sample size are required to investigate the efficiency of acupuncture for treating hot flash in patients with breast cancer.”

What follows from all this?

  • The collective evidence does NOT seem to suggest that acupuncture is a promising treatment for hot flushes of any aetiology.
  • The new paper is unimpressive, in my view. I don’t see the necessity for it, particularly as it fails to include a formal assessment of the methodological quality of the primary studies (contrary to what the authors state in the abstract) and because it merely includes articles published in English (with a therapy like acupuncture, such a strategy seems ridiculous, in my view).
  • I predict that future studies will suggest an effect – as long as they are designed such that they are open to bias.
  • Rigorous trials are likely to show an effect beyond placebo.
  • My own reviews typically state that MORE RESEARCH IS NEEDED. I regret such statements and would today no longer issue them.

Use of complementary and alternative medicine (CAM) is common among cancer patients, not least because all sorts of claims are being made for CAM. One of these claims is that it prolongs survival.  But does it improve survival? This new study from the US was aimed at finding out; specifically, the authors wanted to determine whether CAM use impacts on the prognosis of breast cancer patients.

Health Eating, Activity, and Lifestyle (HEAL) Study participants (n = 707) were diagnosed with stage I-IIIA breast cancer. Participants completed a 30-month post-diagnosis interview including questions on CAM use (natural products such as dietary and botanical supplements, alternative health practices, and alternative medical systems), weight, physical activity, and comorbidities.

Outcomes were breast cancer-specific and total mortality, which were ascertained from the Surveillance Epidemiology and End Results registries in Western Washington, Los Angeles County, and New Mexico. Cox proportional hazards regression models were fit to data to estimate hazard ratios (HR) and 95 % confidence intervals (CI) for mortality. Models were adjusted for potential confounding by socio-demographic, health, and cancer-related factors.

Among the 707 participants, 70 breast cancer-specific deaths and 149 total deaths were reported. 60.2 % of participants reported CAM use post-diagnosis. The most common CAM were natural products (51 %) including plant-based estrogenic supplements (42 %). Manipulative and body-based practices and alternative medical systems were used by 27 and 13 % of participants, respectively. No associations were observed between CAM use and breast cancer-specific (HR 1.04, 95 % CI 0.61-1.76) or total mortality (HR 0.91, 95 % CI 0.63-1.29).

The authors concluded that CAM use was not associated with breast cancer-specific mortality or total mortality. Randomized controlled trials may be needed to definitively test whether there is harm or benefit from the types of CAM assessed in HEAL in relation to mortality outcomes in breast cancer survivors.

These findings tie in with the results of several other studies, some of which even seem to show that cancer patients who use CAM die sooner than those who don’t. I have previously pointed out that this could have several reasons, for instance:

1) Some patients might use ineffective alternative therapies instead of effective cancer treatments thus shortening their life and reducing their quality of life.

2) Other patients might employ alternative treatments which cause direct harm; for this, there are numerous options; for instance, if they self-medicate St John’s Wort, they would decrease the effectiveness of many mainstream medications, including some cancer drugs.

3) Patients who elect to use alternative medicine as an adjunct to their conventional cancer treatment might, on average, be more sick than those who stay clear of alternative medicine.

Therefore, I totally agree with the conclusions of the present paper: Randomized controlled trials may be needed to definitively test whether there is harm or benefit…

The risks of consulting a chiropractor have regularly been the subject of this blog (see for instance here, here and here). My critics believe that I am alarmist and have a bee in my bonnet. I think they are mistaken and believe it is important to warn the public of the serious complications that are being reported with depressing regularity, particularly in connection with neck manipulations.

It has been reported that the American model Katie May died earlier this year “as the result of visiting a chiropractor for an adjustment, which ultimately left her with a fatal tear to an artery in her neck” This is the conclusion drawn by the L.A. County Coroner.


According to Wikipedia, Katie tweeted on January 29, 2016, that she had “pinched a nerve in [her] neck on a photoshoot” and “got adjusted” at a chiropractor. She tweeted on January 31, 2016 that she was “going back to the chiropractor tomorrow.” On the evening of February 1, 2016, May “had begun feeling numbness in a hand and dizzy” and “called her parents to tell them she thought she was going to pass out.” At her family’s urging, May went to Cedars Sinai Hospital; she was found to be suffering a “massive stroke.” According to her father, she “was not conscious when we got to finally see her the next day. We never got to talk to her again.” Life support was withdrawn on February 4, 2016.

Katie’s death certificate states that she died when a blunt force injury tore her left vertebral artery, and cut off blood flow to her brain. It also says the injury was sustained during a “neck manipulation by chiropractor.” Her death is listed as accidental.

Katie’s family is said to be aware of the coroner’s findings. They would not comment on whether they or her estate would pursue legal action.

The coroner’s verdict ends the uncertainty about Katie’s tragic death which was well and wisely expressed elsewhere:

“…The bottom line is that we don’t know for sure. We can’t know for sure. If you leave out the chiropractic manipulations of her neck, her clinical history—at least as far as I can ascertain it from existing news reports—is classic for a dissection due to neck trauma. She was, after all, a young person who suffered a seemingly relatively minor neck injury that, unbeknownst to her, could have caused a carotid artery dissection, leading to a stroke four or five days later… Thus, it seems to be jumping to conclusions for May’s friend Christina Passanisi to say that May “really didn’t need to have her neck adjusted, and it killed her.” … Her two chiropractic manipulations might well have either worsened an existing intimal tear or caused a new one that led to her demise. Or they might have had nothing to do with her stroke, her fate having been sealed days before when she fell during that photoshoot. There is just no way of knowing for sure. It is certainly not wrong to suspect that chiropractic neck manipulation might have contributed to Katie May’s demise, but it is incorrect to state with any degree of certainty that her manipulation did kill her.”

My conclusions are as before and I think they need to be put as bluntly as possible: avoid chiropractors – the possible risks outweigh the documented benefits – and if you simply cannot resist consulting one: DON’T LET HIM/HER TOUCH YOUR NECK!

The placebo response might be important in clinical practice, but it is certainly difficult to study and the findings of such investigations can be confusing. This seems to be exemplified by two new trials.

The first study examined the possibility of using theatrical performance tools, including stage directions and scripting, to reproducibly manipulate the style and content of a simulated doctor-patient encounter and influence the placebo response (defined as improvement of clinical outcome in individuals receiving inactive treatment) in experimental pain.

A total of 122 healthy volunteers were exposed to experimental pain using the cold pressor test and assessed for pain threshold and tolerance before and after receiving a placebo cream from a “doctor” impersonated by a trained actor. The actor alternated between two distinct scripts and stage directions. One script emulated a standard doctor-patient encounter (scenario A), while the other emphasized elements present in ritual healing such as attentiveness and strong suggestion (scenario B).

The placebo response size was calculated as the % difference in pain threshold and tolerance after exposure relative to baseline. Subjects demonstrating a ≥30% increase in pain threshold or tolerance relative to baseline were defined as responders. Each encounter was videotaped in its entirety.

Inspection of the videotapes confirmed the reproducibility and consistency of the distinct scenarios enacted by the “doctor”-performer. Furthermore, scenario B resulted in a significant increase in pain threshold relative to scenario A. This increase derived from the placebo responder subgroup; as shown by two-way analysis of variance (performance style, F = 4.30; p = 0.040; η(2) = 0.035; style × responder status interaction term, F = 5.21; p = 0.024) followed by post hoc analysis showing a ∼60% increase in pain threshold in responders exposed to scenario B (p = 0.020).


Performance style and response size in placebo responders and non-responders. Bars represent mean ± SE of % change in CPT threshold of 60 subjects in scenario A: 53 non-responders vs. 7 responders and 62 subjects in scenario B: 51 non-responders and 11 responders. Two-way ANOVA by performance style and responsiveness revealed significant effects of doctor’s performance (F = 4.30; p = 0.040; η2 = 0.035) and responsiveness (F = 134.71; p < 0.001) as well as a significant interaction term (F = 5.21; p = 0.024). p = 0.020, Fisher’s least significant difference post hoc test.

The authors concluded that these results support the hypothesis that structured manipulation of physician’s verbal and non-verbal performance, designed to build rapport and increase faith in treatment, is feasible and may have a significant beneficial effect on the size of the response to placebo analgesia. They also demonstrate that subjects, who are not susceptible to placebo, are also not susceptible to performance style.

In the second study, the authors investigated if an implicit priming procedure, where participants were unaware of the intended priming influence, affected placebo analgesia.

In a double-blind experiment, healthy participants (n = 36) were randomized to different implicit priming types; one aimed at increasing positive expectations and one neutral control condition. First, pain calibration (thermal) and a credibility demonstration of the placebo analgesic device were performed. In a second step, an independent experimenter administered the priming task; Scrambled Sentence Test. Then, pain sensitivity was assessed while telling participants that the analgesic device was either turned on (placebo) or turned off (baseline). Pain responses were recorded on a 0-100 Numeric Response Scale.

Overall, there was a significant placebo effect (p < 0.001), however, the priming conditions (positive/neutral) did not lead to differences in placebo outcome. Prior experience of pain relief (during initial pain testing) correlated significantly with placebo analgesia (p < 0.001) and explained 34% of placebo variance. Trait neuroticism correlated positively with placebo analgesia (p < 0.05) and explained 21% of placebo variance.

The authors concluded that priming is one of many ways to influence behaviour, and non-conscious activation of positive expectations could theoretically affect placebo analgesia. Yet, we found no SST priming effect on placebo analgesia. Instead, our data point to the significance of prior experience of pain relief, trait neuroticism and social interaction with the treating clinician.

The two studies are similar but generate somewhat contradictory results. In the discussion section, the authors of the first paper stress that “replication of our findings in clinical populations; employing professional physicians of both sexes, are necessary in order to establish their generality and possible application in medical training, with the aim of improving patient outcome across diseases and treatment modalities.” This is certainly true. They continue by stating that  “future studies using performance tools in clinical trial settings could demonstrate the potential of borrowing performance principles and techniques from traditional healing and applying them to physician–patient encounters in Western medicine, following certain necessary modifications. Performance tools could thus eventually be incorporated into the systematic training of physicians and medical students, possibly to complement programs in Narrative Medicine and Relational Medicine.”

These ideas are not dissimilar to what we have been discussing on this blog repeatedly. For instance, I have previously tried to explain that “the science and the art of medicine are essential elements of good medicine. In other words, if one is missing, medicine is by definition  not optimal. In vast areas of alternative medicine, the science-element is woefully neglected or even totally absent. It follows, that these areas cannot be good medicine. In some areas of conventional medicine, the art-element is weak or neglected. It follows that, in these areas, medicine is not good either.”

The fact that the two studies above show contradictory findings is not easy to interpret. Possibly, this shows how fragile the placebo response can be. It can be influenced by a multitude of factors related to an experiment or the clinical setting. If that is so, and placebo effects are truly unreliable, it would be yet another argument for not relying on them in clinical routine. In my view, clinicians should try to maximize them where they can. Yet placebo effects are not normally a justification for employing placebo therapies in clinical practice. In other words, the fact that a bogus treatment can generate a placebo response is not a good reason for using it on patients who need help.

Good clinicians have probably always been good ‘performers’. Alternative practitioners tend to be excellent ‘performers’, and I am sure their success is mainly due to this ability. I see little reason why conventional practitioners should not (re-)learn the skills that once upon a time were called ‘good bed-side manners’. Maximizing the placebo effect in this way might maximize the benefit patients experience – and for that we do not require the placebo-therapies of alternative medicine.

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