What is the Placebo Effect and How can it Help us?
''Mr. Wright,''1 was diagnosed with cancer. He was given only days to live. Hospitalized with tumours the size of oranges, he heard that scientists had discovered a serum, that appeared to be effective against cancer. He begged to receive it. His doctor, finally agreed and gave Mr. Wright an injection containing the serum. The following Monday, he found his patient talking with the nurses. The tumours, the doctor wrote later, ''had melted like snowballs on a hot stove.''
Two months later, Mr. Wright read medical reports that the serum was ineffective and possessed none of the healing properties it was perceived to have. He had an immediate relapse. ''Don't believe what you read in the papers,'' the doctor told Mr. Wright. He then proceeded to inject him with what he said was ''a new super-refined double strength'' version of the drug. Actually, it was water, but again, the tumours melted. Mr. Wright was ''the picture of health'' for another two months — until he read a definitive report stating that the serum was worthless. He died two days later. This phenomenon is known as the placebo effect. In this essay I will explore the placebo effect, focusing on possible theories as to how it works as well as looking at the ethical debate surrounding its use as a treatment for patients.
What is the Placebo Effect?
Stewart-Williams and Podd2 defined a placebo as: "a substance or procedure that has no inherent power to produce an effect that is sought or expected.” and the placebo effect as: "a genuine psychological or physiological effect, in a human or another animal, which is attributable to receiving a substance or undergoing a procedure, but is not due to the inherent powers of that substance or procedure." This definition is well respected as it includes the fact that a placebo can take many forms, as physical procedures or taking fake medication, it also includes the fact that animals can also experience the placebo effect. However, it is important to note that this definition does not account for any other factors that may account for the patient's improvement in health, such as natural progression of a disease.
There are two main theories that explain the placebo effect, 'expectancy theory' and 'classical conditioning'.
Expectancy Theory
Expectancy theory states that due to the patient's expectation of a desired effect, the expectation results in the desired effect occurring, similar to the idea of positive thinking.
The science behind expectancy theory is more complicated. One theory as to how it works is based upon the idea of stress reduction. The expectation that the patient holds, that they will feel better after being treated will decrease the amount of stress the patient experiences. This is suggested to increase the functioning of the patient's immune system.3 Other potential explanations for the stress reduction theory suggest that the expectation of a relief of symptoms could result in the patients resuming their normal routines, which helps get rid of the symptoms they were originally experiencing.4
The problem with this understanding of expectancy theory is that it fails to account for the placebo effect occurring in healthy individuals, and it also fails to account for side effects which can result from taking a placebo. This is known as the Nocebo effect. To accommodate these objections, Dr Irving Kirsch5 proposed the 'response expectancy theory'. Simply stated if the patient expects a treatment to produce a pain-relieving effect, then they will experience a relief in pain; and similarly, if the patient expects a treatment to produce a decrease in depression, then they will experience a decrease in depression. The advantage of response expectancy theory is that it does not rely on reducing stress to produce its effects, despite this, the expectancy theory approach still struggles to explain situations where an actual physiological response occurs as a result of a placebo which is a significant issue.
Classical Conditioning
Classical conditioning theory in relation to the placebo effect is based on the concept that Ivan Pavlov6 concieved in 1923. Ivan Pavlov was a physiologist studying salivary responses in dogs. As one would expect, he presented them with food to make them salivate, he would then measure the resulting effect. However, what he didn't expect was that otherwise irrelevant stimuli were also capable of causing salivation in dogs. The dogs would begin to salivate before the food was presented. This caused Pavlov to deduce that there must be some other cue that the dogs were using to predict that food was about to come, for example, the sound of the researcher's footsteps as they came down the hallway with the food. In order to test this, he looked at the effect a neutral stimulus, the sound of a bell, would have when associated with the food. He did this by ringing the bell when the food was presented. Pavlov found that he had created what he deemed to be a "conditioned stimulus" in the dogs, in simple terms it just means that the sound of the bell, through repeated pairings with the food, had taken on the value of the food, and so in order to make the dogs salivate all he had to do was to ring the bell – the food was no longer necessary to produce this response.
Classical conditioning relation to the placebo effect was discovered by accident in a separate unrelated experiment conducted by Ader and Cohen7. They had been studying the effects of an immunosuppressant (a substance that weakens the immune system) by adding the substance to sweetened water which they gave to rats to see the effect that it would have on their immune system. However, an abnormally high number of their subjects began dying from minor ailments. They suspected that there was another factor that was causing these abnormal deaths. By mimicking the same basic methodology that Pavlov used, the pair discovered that by pairing cyclophosphamide (the immunosuppressant they were studying) with saccharine (sweetened water), they were able to stimulate the same effect as the immunosuppressant on the immune system of the rats. So, like Pavlov's bell, the rats became conditioned to the sugar water, expecting to feel worse when they drank it and consequently did.
The implications of this study are astounding. In essence our ability to deal with certain diseases can be drastically and subconsciously altered by our experiences with the environment around us. For example, when a patient takes a regular pain killer to stop a headache, their body is not only reacting with the drug itself, but also the body is reacting to the context and cues that are linked to the act of taking the pill and the consequences of that action. To put it simply the act of physically receiving a treatment can also cause relief in symptoms. This can be seen in the following table, taken from the Horizon documentary,'The Power of the Placebo'.8
More effective
Less effective
Capsules
Tablets
Large capsules
Small capsules
Expensive medication
Cheaper medication
Red pills for treating pain
Any other colour of pill for treating pain
Blue pills for treating anxiety
Any other colour of pill for treating anxiety
How Does It Work?
The Stewart-Williams and Podd paper 'The Placebo Effect: Dissolving the Expectancy Versus Conditioning Debate' concludes that it is a combination of the two theories that explains the workings of the placebo effect. However, ultimately the answer is unknown, but on the balance of evidence, I believe that this is the most likely theory.
How Could It Help Us?
The placebo effect has the potential to revolutionise medicine, lowering the cost of producing medication and making it more readily accessible to people across the world. Making it easier to mass produce and distribute to those in need due to its simple formula, a sugar pill, sham injection, etc…
The placebo effect may become a more commonly used treatment in our NHS, and could become a large factor in the health of people across the globe. At present in Britain the NHS is suffering due to serious underfunding and understaffing. The Placebo effect could potentially solve this. Between 2014 to 2015 £15.8 billion pounds were spent on drugs. This number could be significantly reduced if hospitals and doctors were to prescribe placebos instead of drugs where appropriate. This sum of money could be used elsewhere and to better effect within the NHS.
However, the ethics of doing this are questionable for numerous reasons. One such reason being the fact that the doctor patient relationship may deteriorate entirely, as patients may not be comfortable with their doctor lying to them. In addition, they may stop trusting the doctors entirely.
Also, when considering a treatment, the doctor must administer a suitable cure that will help the patient. With drugs there is a high chance that the drug will work and the patient will be cured as the drug contains chemicals that will actively work to alleviate the symptoms, the same goes with surgeries and injections, they will actively alleviate symptoms of patients. However, with the placebo, the chance of it working is unknown as people react differently and the placebo can have different ranges of success in treating the disease. The question that poses the doctor is, is it worth taking the risk? Ethically is it right to prescribe a treatment that is riskier but possibly cheaper, or one more likely to work but more expensive?
The Future of the Placebo
Once we understand the Placebo effect we could not only make medicine cheaper, but also perhaps eradicate it entirely. If we discover how the placebo works, we could train our brains to elicit a response similar to the placebo effect, without taking a placebo of any kind. This would be ground-breaking; however, it is entirely theoretical and may not be possible. This ability to heal ourselves would change our world irreversibly and would change the way we see and approach life.
Conclusion
To conclude, the placebo effect is a 'genuine psychological or physiological effect'. How it works still remains a mystery, however there are many theories that suggest its workings. There is expectancy theory and classical conditioning. Both of these arguments are strong, making it very difficult for me to pick one or the other. That being said, the most convincing theory that I have come across is that of Stewart-William and Podd. They concluded that the placebo effect was a combination of expectancy theory and classical conditioning. On the balance of evidence that I have seen, this seems to be the most convincing explanation and the one which makes the most sense.
As for the placebos future, I believe that the placebo effect certainly has its place in medicine, however, its place is dependent on our understanding of it. For the moment, it is simply too unpredictable to use in medicine. However, once we understand it better, I firmly believe that it will become an essential part of the medical world. However, for now it remains a truly remarkable phenomenon.
Reflection
I found the task somewhat daunting, however, I approached the task logically by first splitting up the title into a series of smaller sub-topics, which I then began to research. I planned to research each for an equal amount of time and then bring all of the evidence gathered together to create this essay. However, what I found was that certain topics were vastly more complicated than others, they required much more time and effort to understand. I think that giving each topic an equal amount of time was unrealistic, if I do something like this again I will be sure, that I weight the amount of time I dedicate to each topic according to how easy I find it to understand and gather information on the topic. In addition to this, I would like to thank my supervisor, Mr Bailey, for advising me and helping me throughout my project.