The word placebo comes from the Latin, meaning “I shall please”. By the early 19th century, placebo had acquired its modern medical meaning as something “given more to please than benefit the patient”.
Placebos are not just dummy pills, filled with an inert substance. Writing this month in the New England Journal of Medicine, Ted Kaptchuk and Franklin Miller, placebo experts at Harvard University, say it is probably more accurate to speak of placebo effects.
“In a broad sense, placebo effects are improvements in patients’ symptoms that are attributable to their participation in the therapeutic encounter, with its rituals, symbols, and interactions,” they write. In other words, as well as through sham medication, a placebo effect may occur through a process whereby the “doctor is drug”, in which empathy, an emotional engagement with the physician and the laying on of hands all play a part in ameliorating a person’s symptoms.
AJ Cronin, writing of his experiences as a doctor in the Welsh valleys in the 1920s, described the healing power inherent in the colour of liquid medicine. A cough medicine made with the “wrong” colour simply did not work for his patients. Similarly, Kaptchuk and Miller describe a migraine study showing how the placebo effect of symbols can enhance the effectiveness of pharmaceuticals dramatically.
Self-healing
Harvard researchers have previously shown that placebos are effective even when the patient is told they are being given an inert pill.
The researchers explained to 80 volunteers with irritable bowel syndrome (IBS) that half of them would receive no extra treatment and the other half would receive a placebo. They outlined to participants that this was a sugar pill that had been found to “produce significant improvement in IBS symptoms through mind-body self-healing processes”. Patients were then randomly either assigned the pill – in a bottle clearly marked placebo – or told to continue their regular treatment for the condition.
When reassessed after 11 days, and again at 21 days, the patients given the placebo reported better pain relief and greater reduction in the severity of other symptoms than those who got no pill.
The authors concluded: “Placebos administered without deception may be an effective treatment for IBS. Further research is warranted in IBS, and perhaps other conditions, to elucidate whether physicians can benefit patients using placebos consistent with informed consent.”
This study challenges the conventional wisdom that placebo effects require a doctor to intentionally deceive a patient. The results suggest that doctors can behave ethically if they describe clearly what is known about placebo effects, encourage the patient to suspend disbelief, and “sell” the inert treatment in a way that encourages a positive outcome.
The latest neurophysiological research strengthens the case for a placebo effect. During experiments with placebos, specific neurotransmitters, including endorphins and dopamine, have been shown to activate certain parts of the brain such as the prefrontal cortex and the amygdala. And with evidence emerging that genetic variations in these pathways can modify placebo effects, it raises the possibility of using genetic screening to identify placebo responders.
Could a predisposition to respond to placebo treatment be, in part, a heritable trait? Just as the power of the microbiome is fast emerging, could we one day identify the genes involved in a “placebome”?
Noting placebo effects are often considered “unworthy and illegitimate”, Kaptchuk and Miller say such an attitude obscures a core truth of medicine: “medicine’s goal is to heal, which can include cure, control of disease, and symptom relief or provision of comfort. When no cure is available – an inevitable occurrence at some points – medicine’s ultimate mission is to relieve unnecessary suffering.
“Of course, placebo effects are modest as compared with the impressive results achieved by lifesaving surgery and powerful, well-targeted medications. Yet we believe such effects are at the core of what makes medicine a healing profession.”
mhouston@irishtimes.com muirishouston.com