In science, the placebo is a placeholder administered to the control group in experimental studies. Researchers interpret the “real effect” of whatever they’re examining with a mathematical equation: R = T – P. It’s the difference between the effect in the experiment group (total effect) and the effect in the control group (Lynoe, 1990).
Most research and arguments for or against the validity of a placebo response all go back to the work of Dr. Henry Beecher from his 1955 article The Powerful Placebo. He actually developed the RCT – randomized control trial – which is the model of pharmaceutical testing that has been used ever since. Split a group in half randomly, give one group a real drug, give the other a fake drug, and see how the real one performs. The whole point of the placebo is to test the effect of the other thing.
Meaning vs. Mechanism
What is the placebo effect? It’s an effect produced by the placeholder. The effect is generally attributed to the subject’s belief in the treatment. Scholars are generally split between two general theories on why this happens: meaning vs. mechanism (LeBlanc, 2014).
The meaning side of the divide has to do with symbolism and cultural factors. If the placebo is a pill and it has a brand name on it versus not having any brand name at all, it works better. If it’s expensive, or if it’s an injection rather than a pill, it works better. We trust doctors with good bedside manner more than those without it. These factors influence our expectancy of the outcome; this is actually it’s own theory (expectancy theory), which is more psychological rather than cultural, but involves similar factors of symbolism and belief.
The mechanism side of things is about conditioning (i.e. Pavlov’s dogs). It compares the placebo effect to a type of associative learning. Perhaps you’ve taken ibuprofen for pain relief a hundred different times; you associate ibuprofen with pain relief. If you took unknowingly took a placebo of ibuprofen, it might produce the same results.
A lot of debate amongst these theorists revolves around the idea of cause and effect. The layman may simplify his understanding of the placebo effect as the subject’s brain causing a physiological response.
This effect has been observed in scientific study for decades. In most cases, however, it is not the part of the research that is actually being studied. It may have a name, but is generally considered an irrational effect peripheral to serious scientific interest (Lynoe, 1990).
Placebo in Biomedicine & Alternative Healing
In clinical drug trials, we have some neurobiological evidence that the expectancy of an opioid-like effect from a placebo medication can activate the brain’s pain-modulating pathways (Hedges & Burchfield, 2005). This is similarly the case with other parts of the brain and different types of placebo – i.e. blood pressure and psychomotor performance changes with placebo caffeine, and brain metabolic fluctuations with placebo depression medication.
An interesting article by Ted Kaptchuk (2011) compares the symbols and tools used in Navajo healing ceremonies, acupuncture, and biomedicine. The author surmises that all three healing opportunities can be said to provide the following:
- An evocation of space, time and words separate from the ordinary
- A pathway of enactment that guides and envelops the patient
- A concrete ebodiment of potent forces
- An opportunity for evaluation of a new status
Additionally, an older body of research (Csordas, 1983) explains three stages of inward experience that a patient undergoes in a healing ritual: a predisposition to be healed, an experience of empowerment, and a concrete perception of transformation. I can picture this application in several different scenarios. The first thing I think of is going to the doctor for a health problem, being diagnosed and prescribed, and undergoing treatment. No matter the precise situation, I certainly experience those three steps.
Another very interesting point from Kaptchuk is that while something like a Navajo healing ceremony is explicitly religious and cultural, Western biomedicine is explicitly devoid of any belief-based system and strictly concerns evidence-based knowledge. This fact may actually give biomedicine an additionally charged symbolic power. The power of science comes with its own enigmas. Most of us aren’t doctors, but most of us blindly trust doctors. Because science.
There are also studies that have been done about overt versus covert medical treatments (Colloca, Lopiano, Lanotte, Benedetti, 2004) where proven powerful medications were administered to patients without them seeing it happen, and the medications would have significantly less effect or no effect at all. Is the ritual of being told by a doctor that you are receiving an anti-anxiety medicine part of the actual treatment?
Kaptchuk seems to appear in a lot of research about the placebo effect. A 2021 article from Harvard Health quotes him: “Placebos may make you feel better, but they will not cure you. They have been shown to be most effective for conditions like pain management, stress-related insomnia, and cancer treatment side effects like fatique and nausea.”
Effect vs. Response
In a book chapter about opioids (Dolphin-Krute, 2018), the author chooses to use the phrase placebo response rather than placebo effect to highlight the “interconnectedness of personal experience and biology” and states that the word effect suggests something that only happens to you, rather than something that you are involved in producing. I like this.
Things That Are Definitely True:
- There is a real, observable phenomenon that happens in the brains of placebo subjects in many scientific studies. The results aren’t always clear, understood, or considered meaningful.
- We know a lot about the human brain and which parts of it have specific functions, but there is a lot about the human brain that we do not understand.
- There is strong evidence that the placebo response is associated with significant changes in brain chemistry and function (Hedges & Burchfield, 2005).
- Placebo effects are often described as non-specific. Essentially every aspect of worthy scientific study is supposed to be specific.
- In any placebo response, context matters. The response as a whole factors in both physiological mechanisms and personal subjective experiences and beliefs.
Seeing is believing? Believing is seeing?
Somewhere, I’ve heard that magic is just science before we understand it.