Placebos Can Fool Your Mind, but Not Your Body
Here is a neat experiment demonstrating how the minds of people with asthma can be tricked by placebos, but not their bodies.
It is not meant to be a story about people with asthma, but about all of us — how we are susceptible to certain kinds of illusions when we use our subjective feelings to determine if a treatment is effective for something that ails us.
Placebos are greatly misunderstood by professionals, not just laypersons. Placebos are not magic. They do not produce measurable body change. If a substance produces measurable body changes, it is not a placebo.
What is a placebo? Something that being performed or provided with positive expectations and social support for someone believing that it is effective, plus the passage of time.
A lot of adults take a single aspirin for a headache. The headache goes away.
But one aspirin is too low a dosage for reducing pain. The headache was going to go away without the aspirin. A randomized clinical trial (RCT) could easily show that.
The problem is that people do not typically conduct their own RCTs. They judge what works by before/after comparisons of their subjective experiences.
People can be tricked into believing that something has affected a change in their bodies if there is a ritual and they experience something as being different about them. The ritual can be as simple as taking a pill or can involve more hocus pocus.
Suggestions from someone we consider an authority or something we read on social media can increase our susceptibility to a placebo effect.
Sometimes culture influences beliefs in what “works” as a placebo. That is currently the case with cannabidiol (CBD), although some people will disagree with me about using CBD for some conditions.
At your local grocery store, particularly if it is a co-op staffed by New Age people or aging hippies, there are probably more placebos than active, effective medications for sale.
Many people are convinced that acupuncture reduces their pain. But they can also be convinced by a sham procedure consisting of needles being inserted into them in what acupuncturists would say are all the wrong places.
I know, a lot of people are convinced that acupuncture has done wonders for them. But if they had instead gotten sham treatments by an acupuncturist who was enthusiastic and nice, but did not know what they were doing, I’d bet the same subjective would have been produced.
People are convinced that the Headspace app produces profound changes in them. Yet, when people are given fake Headspace instructions, they provide self-reports of their mental states that are indistinguishable from what is reported by people who got the usual instructions from the Headspace platform.
I’ll take back what I say about the Headspace app if someone provides me with compelling evidence of its effectiveness.
Claims about the magic power of the placebo arise when we rely exclusively on subjective self-report and have no objective measures we can check. That is a lot of the time.
With pain and mood states, we typically do not have objective measures. Pain is very real, but we are generally not good at measuring it objectively, except maybe its interference with daily life.
So, what is the harm in treating pain and mood with placebo interventions?
Placebo effects tend to be temporary.
People waste millions, perhaps billions of dollars on them.
At your local grocery store, particularly if it is a co-op staffed by New Age people or aging hippies, there are probably more placebos than active, effective medications for sale.
It is tough to tell the difference between the medications that have proven effectiveness and placebo. Don’t ask the staff at your co-op. They will probably tell you their experiences with the placebos are better. They cite testimonials from their friends and family and what they saw as amazing changes in their dog when they gave her CBD.
Reliance on placebos delays people from seeking more effective treatment.
Some pills are allowed by the US Food and Drug Administration to be advertised as antidepressants. That is because clinical trials have shown that when research participants are provided with them after proper diagnosis and education, they on average improve more than persons who have been given inert pills with the same diagnosis and similar encouragement that pills will improve their mood.
It requires a randomized controlled trial to establish that a pill is an antidepressant. There are a lot more substances that have been tested by drug companies to see if they are antidepressants and failed the test than ones that have been approved. Most promising candidates fail in the comparison with an inert pill if they even get that far.
I think the following study is quite fascinating. The research participants were recruited because they had well-controlled asthma but were willing to consent to an experiment in which they might be given something that was not known to be a treatment. Medical science depends on the goodwill of such people.
The investigators were not interested in asthma. Rather they needed research participants who had a medical condition for which objective, as well as subjective measures, were available.
The study compared a well-established treatment with sham acupuncture and fake inhalants to effective treatment, albuterol.
It was quite nice of the prestigious New England Journal of Medicine to make this study, freely available, open access. Just click on the link below to get your own copy.
Wechsler ME, Kelley JM, Boyd IO, Dutile S, Marigowda G, Kirsch I, Israel E, Kaptchuk TJ. Active albuterol or placebo, sham acupuncture, or no intervention in asthma. New England Journal of Medicine. 2011 Jul 14;365(2):119–26.
This randomized, double-blind, crossover pilot study involved screening 79 patients.
A total of 46 with mild-to-moderate asthma met the entry criteria. After consenting to be in the study, they were randomly assigned to one of four study interventions.
Treatment using an inhaled albuterol bronchodilator was compared to one of three control conditions placebo inhaler, sham acupuncture, or no intervention.
Albuterol is well established as an effective treatment to relieve breathing problems in people with asthma.
Below low is Figure 4 from the article. It is a bar chart of subjective outcomes for two self-report measures, perceived improvements in asthma symptoms on a visual analog scale and perceived credibility of treatment.
You don’t have to be a statistician to see this bar graph produced compelling results that the two placebo treatments were as good as albuterol for producing subjective changes in breathing. All were better than nothing, no intervention.
Patients reported substantial improvement not only with inhaled albuterol (50% improvement) but also with inhaled placebo (45%) and with sham acupuncture (46%).
In contrast, the improvement reported with no intervention was only 21%.
The difference in the subjective drug effect between the active albuterol inhaler and the placebo inhaler was not significant (P=0.12), and the observed effect size was small (d=0.21).
So, there was no advantage to what is known to be an effective treatment versus the same inhaler with a fake drug in it.
As for the placebo effect, the difference between the two placebo interventions and no intervention was large (d=1.07 for placebo inhaler and d=1.11 for sham acupuncture) and significant (P<0.001 for both comparisons).
Patients were really fooled in this study. When they were not given anything, not even a ritual, their subjective reports did not change. When they were given fake procedures, they reported their breathing improved — just like when they were given an effective medication.
The credibility of the supposed treatment was high, and most patients believed that they had received active treatment (73% for double-blind albuterol, 66% for double-blind placebo inhaler, and 85% for sham acupuncture).
The two double-blind conditions did not differ significantly from each other, but sham acupuncture was significantly more credible than both inhaler conditions (P<0.05).
Sham acupuncture had more going for it than real or fake drugs delivered in the inhaler. Presumably, the sham was provided with more of a fuss and so seemed like an experimental treatment.
So far, placebos are powerful and patients thought the sham acupuncture as the real or fake drug in the inhaler.
Figure 3 from the article presents the outcomes for an objective measure of physiological responses — improvement in forced expiratory volume (FEV1), measured with spirometry. Data are presented for each intervention (albuterol inhaler, a placebo inhaler, sham acupuncture, and no intervention) across the three study visits.
The mean percent improvement in FEV1 was 20.1±1.6% with inhaled albuterol, as compared with 7.5±1.0% with inhaled placebo, 7.3±0.8% with sham acupuncture, and 7.1±0.8% with the no-intervention control.
There were no significant differences between the three inactive interventions, none of which resulted in the degree of improvement observed with active albuterol.
The difference in drug effect between the albuterol inhaler and the placebo inhaler, as indexed by the difference in mean percent improvement in FEV1, was significant (P<0.001) and large (d=1.48).
In contrast, the placebo effects did not differ significantly between the two placebo interventions and the no-intervention control (P=0.65 for the comparison of placebo inhaler with no intervention, and P=0.75 for the comparison of sham acupuncture with no intervention).
The authors concluded:
“In this repeated-measures pilot study in which active-drug and placebo effects were assessed in patients with asthma, two different types of placebo had no objective bronchodilator effect beyond the improvement that occurred when patients received no intervention of any kind and simply underwent repeated spirometry (no-intervention control). In contrast, the subjective improvement in asthma symptoms with both inhaled placebo and sham acupuncture was significantly greater than the subjective improvement with the no-intervention control and was similar to that with the active drug.”
I am an evidence-based skeptic. I do not like being fooled. I am aware I have cognitive biases, particularly because I think I know a lot. I need a kind of reminder every now and then I forget that I can be a confident fool.
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