The Real Magic of the Placebo
The real magic of the placebo, was convincing the world that is does something good. This leads to a slippery slope were placebo therapies are given apparent legitimacy. Really placebos do nothing, nada, zip, bupkis. Their primary function is to measure the background bias in an experiment, most frequently reporting bias (more on this later.)
The idea of a magic placebo is very prevalent in medicine, often falsely and naively attributed to mind over matter, which I think can be very harmful. Since this can easily lead to patients blaming themselves for not getting better, because of mistaken belief they didn’t have the right mindset, which is far from the truth.
Why do people think it works?
In Ben Goldacre’s book “bad science” he lists several situations where placebos have apparently shown beneficial effect. Including operating on a soldier with horrific injuries in World War II field hospital. Using only salt water because they had run out of moraine, the patient was fine. Actually there is no evidence that this ever happened, it is just a myth.
Other results mentioned on Ben’s book showed that a placebo injection is more powerful than a pill, larger numbers of pills work better than fewer; capsules are more effective than tablets; and a large pill is more effective than a small pill. Elaborate rituals are better than simple ones; branded placebos are more effective than generic; expensive treatments work better than cheap ones. Placebo morphine is more effective than placebo propoxyphene, which is more effective than placebo aspirin. Placebo and active analgesics are more effective when presented with a well-known brand name. The colour of a placebo is influential Pink pills improve mood, while blue ones depress, whereas red placebos induce stimulant effects. Patients report falling asleep more quickly after taking a blue capsule than after taking an orange capsule. Red placebos seem to be more effective pain relievers than white, blue or green placebos. The magnitude of the placebo response varies as a function of the stated dose consumed. (Daniel McQueen et al)
All these benefits are for subjective things, like “how do you feel” “rate you pain on a scale of 1 to 10” and are therefore very susceptible to bias. The Placebo doesn’t work on objective measures, like did your tumour reduce.
In long covid if we asked “do you feel less fatigued” we could get a placebo effect. But if we actually measure your actively levels, or number of steps with a smart watch the object measurement destroys the placebo effect.
There are plenty of reports of the benefits of placebo effects, even from apparently credible sources such as Harvard medical school, and the conversation.
Fewer places seem to have the placebo effect described correctly, but Science Based Medicine and Cambridge have, go there for a even deeper dive. Also listen to the excellent Mike Hall on Skeptics with a K, (pictured with me) as that boy really knows his placebos! He inspired this article, Thanks Mike!
So what is going on here?
Are the psychological effects of taking a placebo causing changes in the brain, which affect the bodies’ physiological response to illness, or is it all in the patient’s head. First we need to understand if there a difference between the nothing of no treatment and the nothing in a placebo i.e. would these improvements have been seen if people had not had a placebo. A Cochrane review has been conducted in this field, which studied 202 trails comparing placebo to no treatment found that it found that:
“In general, placebo treatments produced no major health benefits, although on average they had a modest effect on outcomes reported by patients, such as pain.”
Even on patient reported outcomes the effect varied from large to nonexistence. One of the authors of this paper Dr. Hrobjartsson a professor of medical philosophy and research methodology at University of Copenhagen, said:
“The high levels of placebo effect which have been repeatedly reported in many articles, in our mind are the result of flawed research methodology.”
Couple this with the information that the placebo effect is virtually non-existent for objective outcomes related to physical or mental disease. This would indicate that placebos are indeed doing nothing clinical and the effect is purely psychological, and reporting. bias. All a placebo did was make the patient feel better about having an illness but there was no magical effect, which caused someone taking a sugar pill to get better. This is just reporting that they felt better, they probably did feel better and there are a whole host of reasons why that might happen:
So why all the positive effects from a sham treatment:
•The immune system has evolved to help it survive and sometimes people just exhibit spontaneous improvement, time is a great healer.
•Regression to the mean. Some of the improvement observed will be the result of the fluctuation of symptoms, Symptoms will wax and wane over time, , extremes are less common and have the tendency to become closer to the mean when repeated, also people are likely to seek treatment when they feel such extremes. Get Acupuncture when you feel at your worse, then the natural swing towards less sever symptoms might convince you that the magic needles worked, when they did nothing.
•People may get additional treatment, which hasn't been controlled for in the testing, hence another factor is causing improvement. Parallel interventions are where patients take something else, some other active treatment, at the same time as the placebo. Unrecorded parallel interventions are where patients not only take something else, but they don’t even tell their doctor they’re doing it. Or if they do, the doctor doesn’t write it down.
•There are times when people will just give incorrect answers in these subjective questions, not to be confused with lying this could just be answers of politeness, experimental subordination, conditioned answers, neurotic or psychotic misjudgment, psychosomatic phenomena, misquotation, etc.
•Recruiting patients through financial inducements incentivises them to exaggerate their symptoms (consciously or not) so as to meet the study entry criteria. Later they appear better. This isn’t that egregious, if visiting a doctor, you should describe how you feel on your worst days, not how you feel today.
•Also more compex reason such as conditional switching of placebo treatment, scaling bias, irrelevant response variables, will have an affect.
All this suggests that the large effect of placebo interventions could be an artefact of inadequate research methods. None of this implies that placebo responses involve a real biological “healing” mechanism. Reporting an improvement maybe purely psychological and not a real improvement in health. All the reports of major health benefits due to placebo may be cherry picking through the data rather than looking at the literature as a whole. Really this all adds up to placebo effect measuring the underlying bias in an experiment, not magic "mind over matter".
So why have placebos at all?
Most medicines need testing v’s placebo in order to get a decent picture of the safety profile. It works very well as a comparison if there is currently nothing that is known to work.
However, if there already is a treatment, doctors need to know how new treatment compares to the old, not how it compares to placebo. So trials which compare two treatments against each other yield more usable data, and all participants in the trail get a valid treatment, old or new.
This means that trails using a placebo when there already is treatment is unethical, since using a placebo arm they may be depriving half the study participants of valid treatment, and the data isn’t as useful to doctors as a comparison to the old treatment.
“Prior studies have consistently shown that for subjective symptoms such as this the interaction with the practitioner is the single most important factor in reporting a subjective improvement in symptoms from a placebo intervention.”
Dr. Steven Novella
"Complementary and alternative medicine generally takes place in pleasant environments, and is provided by practitioners who listen to their patients and their concerns, make them feel validated, reassure, promise hope and who generally themselves believe in the effectiveness of their treatments. They may also have more time for their patients than state-salaried clinicians in the National Health Service. All of these factors maximise placebo response” Daniel McQueen et al
This would imply that a doctor or caregiver can give a suitable placebo effect though good bed side manner and spending time with a patient without the need for dummy pills or treatments. Unfortunately medical doctors are extremely busy and usually have only a few minutes to spend with a patient. A provider of supplements, complementary and alternative Medicines (SCAM’s) will most likely have a lot more time to spend with each of their patients so they will therefore observe a greater placebo effect; which they could easily confuse for a real health benefit due to their ineffective treatment. Hence a big problem related to placebo effect is that patients can become dependent on non-scientific practitioners who employ placebo therapies. When all they really needed was a little time with someone.