Ask the Doctor: The placebo effect revisited

For those who follow my column regularly, about 2-3 years ago I wrote an article on the power of placebos. To refresh your memory, a placebo is defined as “an ineffective treatment believed to be effective”. As long as the patient believes that a given treatment is “real”, no matter how ineffective or even bad it is, he/she will experience a positive effect. We develop placebo responses with all kinds of treatments (medications, injections, surgery, creams and lotions, manual and other therapies and the list goes on).  Ineffective treatments acting as placebos can relieve our pain, abnormal posture, wheezing and even symptoms of cold, fatigue, muscle aches, heart aches, anxiety etc.  Scientific studies have shown impressively that success rates with placebos can be as high as 70 per cent!

I also discussed the reasons placebos work. One of the mechanism relate to the positive interaction between patient and caregiver, as this shapes expectations. However, it is more than this: the type of facility in which one is treated, the mode of administration of the placebo (injection versus pill) and even the looks and colour of the placebo, play a role in the generated effect. For example, red capsules are more effective than yellow or white ones, injections are more effective than pills, and treatments that cost a lot bring better results than “cheap” treatments! Another mechanism relates to the chemicals that are missing in different  conditions and are mobilized by the placebo effect. For example, our natural pain killers, the “endorphins”, block pain. Placebos mobilize our endorphins and relieve pain.  In patients with Parkinson’ s disease who have tremors and rigidity, administration of a placebo drug releases the body’s own dopamine (the specific chemical missing in this disease), and the patients get better.

The reason I thought we should revisit the placebo effect, is because I came across a very interesting study (Waber RL, Shiv B, Carmon Z, Ariely D. Commercial effects of placebo and Therapeutic Efficacy, JAMA 2008;299(9): 1016-1017). The researchers recruited 82 healthy volunteers from Boston, Massachusetts using online advertisement. The participants were informed about a (presumably) new opioid drug for pain that had to be tested (though this was an inactive pill=placebo). The group was randomly split in two subgroups. One subgroup was informed that the new medication was costing $2.50 per pill and the other subgroup only $0.10 per pill, as the drug had been discounted. Then after signing formal consent the participants received electrical shocks to the wrist of voltage calibrated to each participant’s tolerance and rated their pain in a computerized scale BEFORE and AFTER they received the pill.

The results showed that 85.4% of the participants in the regular price subgroup experienced pain relief after taking the pill as compared to 61% of the discounted pill subgroup. Additionally, the pain relief was greater for the regular price subgroup than the discounted pill subgroup.

The authors commented that their results were similar to other studies in the literature that described  “commercial variables” affecting response to a medication (in this case price). They went on to discuss that such responses may explain why high cost medical therapies are much more popular than low cost widely available medications, and why patients switched from brand name medications may report that the generic drugs are less effective (though I take issue with this last comment – while the placebo effect of higher priced drugs is just that – a placebo effect –  it has been shown that many generic drugs are not identical to brand name medications, so reduced effectiveness may be a real problem.)

How one can use the placebo effect to modify patient expectations, based on the results of this study? The authors suggested that real effectiveness of medications should be tested with studies not only based on the drug’s chemical structure and mode of delivery, but also how the drugs are sold, i.e., what is their price, packaging or colour of pills. Additionally, since the power of suggestion is an important factor in the generation of the placebo effect, they proposed that physicians who prescribe a drug for a patient, may want to downplay commercial factors that affect negatively the effectiveness of a drug (i.e., that they cost little or that they are generic).

I have said many times before that traditional (Western style) medicine generally undermines the mind-body interaction. The placebo effect is taught very little if at all in our medical schools and ways to generate it or harness it are unknown to most practicing physicians. Maybe one day doctors will learn to utilize placebos properly to mobilize good chemicals within the patients’ body, so that they can augment good effects produced by a treatment and minimize bad ones. Placebos are cheap tools that we all possess and can provide us with ways to utilize our individual mental and chemical powers to our own benefit!

Angela Mailis Gagnon, MD, MSc, FRCPC(PhysMed)

Director, Comprehensive Pain Program,

Senior Investigator, Krembil Neuroscience Centre

Toronto Western Hospital,

Chair ACTION Ontario