What is the placebo effect?
While attending the recent conference of the Committee of Scientific Inquiry in Nashville, TN, another compelling talk was given by Dr. Steven Novella, director of General Neurology at Yale University’s School of Medicine. Along with being a fellow of the Committee of Scientific Inquiry and a popular blogger and podcaster, Dr. Novella is also a well-known media figure who become one of the leaders in the skeptical movement with a focus on debunking alternative medicine claims.
In his talk on the placebo effect, Dr. Novella began by mentioning the ambiguity over exactly what the placebo effect is. “For many years, the placebo effect was considered to be a nuisance effect that needed to be controlled in clinical trials,” Dr. Novella stated. “ More recently, the placebo effect has been redefined as the key to understanding the healing that arises from the medical ritual in the context of the patient\provider relationship and the power of imagination, trust and hope.”
While the medical community recognizes that medically inert substances such as the basic sugar pill can often produce positive medical benefits when patients are deceived about their medical value, this placebo effect has always been controversial (placebo comes from the Latin “I shall please”). Should medical doctors rely on deception to avoid using potentially more dangerous medications? And how effective or reliable is the placebo effect anyway?
Dr. Novella pointed out that advocates of alternative medicine have begun using the placebo effect as a way of marketing their products by stressing that the mind can heal the body in way that medical science cannot understand. “In the context of a clinical trial, the placebo effect is everything other than a physiological response to an active intervention,” Dr. Novella said. “Medical research involves controlling for all possible variables in addition to the actual clinical treatment. The logic of the placebo-controlled trial is to control for as many variables as possible. The problem comes when you start shifting the definition of the placebo around. Most medical research studies aren’t designed to determine what a placebo is exactly.”
Which is not to say that medical researchers have been unable to reach some conclusions about placebos and how they might work. Pharmaceutical companies often base their own products on certain placebo characteristics that appear to influence how patients respond to them. The more expensive the placebo, the longer the placebo effect lasts for patients. Colour of the pill can be important too. For whatever reason, blue sleeping pills are more likely to benefit patients than pills of another colour. Medication to reduce pain are often sold in red pills or capsules since marketing studies showed these to be more effective, etc.
Even when it comes to treatment compliance (a notorious problem with most pharmaceutical medications), patients who take placebos regularly do better than patients who are not compliant with their treatment, regardless of the fact that placebos have no real health benefit. When placebo medications are hard to obtain, more expensive, or otherwise stressed to be valuable to the patient, the placebo effect becomes even stronger.
But how real is the placebo effect? While psychological manipulation can change how patients feel, is there an actual physical effect? Along with the actual treatment effect itself, there is also the reassurance that health professionals can provide to their patient. Simply seeing a health practitioner and being reassured that everything possible was being done can leave a patient feeling hopeful that their condition might improve.
“Physicians are very much aware of the fact that we examine patients, we touch them, and that in and of itself has a physical effect,” Dr. Novella continued. “Being touched in a safe context relaxes and reassures the patient.” There are also non-specific effects in making patients the centre of attention. Bringing them into the doctor’s office and asking questions about their symptoms can make them feel as if they are part of the medical team dealing with the health problem. Different non-specific effects can all contribute to what is regarded as the placebo effect.
Is feeling better the same as actually improving? For “fuzzy” symptoms such as chronic pain, patients are often able to convince themselves that placebos are as effective as actual pain medications. Although the human body continues actual physiological mechanisms to control pain, such as generating endorphins, this is not as reliable as actual pain medication (which is why chronic pain medication is most commonly prescribed by physicians worldwide).
Research looking at the placebo effect usually involves having patients reporting on their own subjective perception of how they are feeling and comparing it to a more objective measure of actual improvement. Intriguingly, Dr. Novella also described a recent study showing that people with high dopamine levels in the brain are more likely to experience placebo effects. Although this result only applies to pain and has still not been replicated, the study does suggest that there is a genetic factor that might be at work with the placebo effect.
As Dr. Novella also mentioned, it is important to look at how diseases can fluctuate over time. Every chronic disease goes through cycles with periods when pain or other distress is most severe and periods of remission when patients are feeling better. When testing a placebo’s value in relieving pain, giving that placebo to a patient when the pain is at its worst will almost certainly lead to pain relief since the pain would have deceased anyway. “This regression to the mean effect is huge”, he said. “And it’s part of the placebo effect too. It’s purely an illusion.”
And the placebo effect varies from disease to disease. Since subjective ratings of pain, depression, or any other symptom being measured cannot be directly compared. It also means that the placebo effect cannot be linked to any particular physical process at work in the body.
Over the past ten years, research comparing actual medical treatments to placebo treatments for various ailments where objective measures of medical improvement were available (such as with asthma) has shown no difference between placebo and no-treatment conditions. When compared to subjective measures however, patients receiving placebos often reported that they felt better regardless of actual improvement.
That’s hardly a surprising finding since most diseases where a placebo effect has been observed, such as pain, asthma, and Irritable Bowel Syndrome (IBS), are also especially vulnerable to psychological factors like stress and anxiety. But even when psychological effects are taken into consideration, the evidence that the placebo effect is actually working seems limited. Whatever relief the placebo provides is usually short-lived and the benefit is purely psychological, not physiological.
There is also the ethical question surrounding placebos. Are medical doctors ethically permitted to deceive patients into believing they are receiving actual treatment instead of a placebo? Even if the medical doctor believes that the patient will benefit? Actually, Dr. Novella argues that deception is not always necessary and some placebo studies with IBS patients showed that placebo effects still relieved symptoms even when the patient knew about the placebo (though this result is controversial).
The real controversy surrounding placebos deals with what the placebo effect actually is what what is means about the human capacity for self-healing. While alternative medicine advocates use the placebo effect as evidence that the brain has the ability to heal physical illness in ways that medicine cannot understand, Dr. Novella points out that this is often exaggerated. He also states that complementary medicine proponents are “feverishly trying to re-brand their products as placebo effects.” In other words, since research has consistently shown that homeopathy, acupuncture etc. tend to be no more effective than the placebo effect, stressing that the placebo effect as a legitimate medical treatment in itself has become a new marketing approach.
In various humorous examples that Dr. Novella provides, the placebo effect is described as “amazing” and “mind-boggling”. One breathless news release described the placebo effect as “proof that God exists” due to its “mysterious nature”. Other news releases stress that alternative medicine can have a “better placebo effect” than regular medicine (which is presumably a good thing).
So, what is the harm of all this? By exploiting the placebo effect in pushing various forms of alternative medicine, patients develop an unrealistic idea of the kinds of benefit this type of treatment can produce. Simply because placebo effects can relieve pain does not mean that the body is capable of curing serious diseases such as cancer (even though many alternative medicine treatments make this claim very quietly).
There have certainly been cases of patients delaying or even rejecting potentially lifesaving medical treatments in favour of alternative medicine. Even in the case of Steve Jobs, at least one medical expert has suggested that Jobs’ skepticism of conventional medicine led and his use of alternative medicine in treating his neuroendocrine tumour may have contributed to his death.
As Dr. Novella stated in concluding his talk, “the harm is instilling bizarre, unscientific beliefs in patients because of exploiting the confusion over the nature of the placebo effect.” That these unsupported beliefs are still leading to very real suffering and even death in patients is something that cannot be ignored.