First Five Years College The nocebo effect in current practice Kalpit Agnihotri MD CCFP ACBOM n 2013, the European Journal of Neurology published seriously ill and extremely weak. From the missionary a meta-analysis examining patient dropout rates he learned that Rob had had a bone pointed at him owing to medication side effects in clinical trials for by Nebo and was convinced that in consequence he IParkinson disease treatments.1 A review of more than a must die. Thereupon Dr. Lambert and the missionary decade of various trials showed that nearly two-thirds went for Nebo, threatened him sharply that his sup- of patients reported an adverse event after drug therapy. ply of food would be shut off if anything happened to Worse still, nearly one-tenth (8.8%) of the patients in a Rob …. At once Nebo agreed to go with them to see specific arm of the studies experienced such horrific side Rob. He leaned over Rob’s bed and told the sick man effects that they were forced to stop treatment altogether. that it was all a mistake, a mere joke—indeed, that Strangely, this subset of patients had not been given any he had not pointed a bone at him at all. The relief, active medication at all—they had been given a placebo. Dr. Lambert testifies, was almost instantaneous; that The placebo arm of a research study is crucial to the evening Rob was back at work, quite happy again, modern scientific method and is used to better under- and in full possession of his physical strength.3 stand the medication and confirm that it gives a true result beyond subjective experience. Much has been writ- A similar example in 20th-century medicine involved ten about the placebo effect in recent years, but lesser Mr Wright and his cancerous tumours.4 Mr Wright suf- known and understood is placebo’s evil twin, the nocebo. fered from advanced lymphosarcoma, but he had faith in a final resort—a horse-serum–derived substance called What is the nocebo effect? Krebiozen. He requested Krebiozen injections from his Nocebo has been defined as physician, and sure enough, his tumours shrank dramat- ically on x-ray scans. He spent several months in good a harmless substance or treatment that when taken health before reports came out stating that Krebiozen by or administered to a patient is associated with had no cancer-fighting properties. Then Mr Wright’s harmful side effects or worsening of symptoms due to tumours returned—visible and larger than ever. negative expectations or the psychological condition His physicians chose to lie to him. They told him that of the patient.2 Krebiozen did indeed cure cancer, but that he needed a much stronger dose for the full effect. Sham treatments To put it simply, bad expectations and “negative vibes” with saline injections caused his cancer to presumably dis- in a clinical encounter involving a prescribed medica- appear completely. Mr Wright lived in good health for sev- tion lead to the patient experiencing real harm as an eral months until a final review by the American Medical outcome. Association conclusively stated that Krebiozen was a useless The idea of “bad vibes” causing harm goes back cen- drug. When Mr Wright learned this, his tumours reappeared. turies. Dr Walter Cannon (the Harvard physician who He was dead within days of admission to the hospital. introduced us to the fight or flight response) discussed In an established patient-physician relationship, this in his well-known article on “voodoo death.”3 patients are often in a highly suggestible state. During Dr Cannon wrote about this phenomenon in various cul- such an encounter, a clinician’s words might be as tures. He observed that the idea that death would result potent as a drug injection. Yet how much thought in from a medicine man pointing a bone at his victim was medical education has been given to this idea? a powerful cultural and spiritual belief. The victim often became hopelessly ill and fatigued over the course of Evidence for the nocebo effect days without any clear cause. It was the nocebo effect at More than anecdotes support the nocebo effect. An arti- its most extreme—a psychologically induced death: cle was published in 2011 titled “The nocebo effect and its relevance for clinical practice,” in which researchers When Dr. Lambert arrived … he learned that Rob examined treatments for benign prostatic hyperplasia was in distress …. Dr. Lambert made the examina- and their side effects, among other therapies for other tion, and found no fever, no complaint of pain, no conditions.5 One group was informed about possible sex- symptoms or signs of disease. He was impressed, ual side effects and the other was not. At 6-month and however, by the obvious indications that Rob was 12-month follow-up, “those patients who were informed 862 Canadian Family Physician | Le Médecin de famille canadien } Vol 66: NOVEMBER | NOVEMBRE 2020 First Five Years about the possibility of sexual dysfunction reported sig- Walking the fine line nificantly greater sexual side effects (43.6%), as compared Our profession obligates us to discuss the common to those who were not informed (15.3%).”5 Investigators and potentially serious side effects of medications concluded that the discussion of potential side effects with patients. No physician should mislead a patient. during informed consent can induce the nocebo effect. Potentially serious side effects should never be con- Various studies have confirmed physiologic mecha- cealed and need to be outlined clearly. However, phy- nisms for the nocebo effect and its ability to produce a sicians should also be aware of the fine line between range of symptoms. An anesthesiology study examined informing a patient of a medication’s side effects and of physiologic processes during pain perception to explain inducing those side effects in a suggestible patient. Additionally, some patients might “talk themselves out increased pain in patients with negative expectations of” taking their medication. In my medical practice, an of pain and anticipatory anxiety.6 Another study used unnecessary and overly detailed review of a dozen pos- functional magnetic resonance imaging to show that sible side effects, often at the request of anxious patients, positive expectations toward the opioid remifentanil has occasionally kept them from starting medications doubled its analgesic effect owing to associations with that would have been beneficial for their overall health. observable activity in endogenous pain modulation in Further, some of the various listed side effects of the brain.7 It has also been proposed that medications often have little or no demonstrated causal- ity and are generally taken from participant comments verbal suggestions of a positive outcome (pain in drug trial reports without much further scrutiny. decrease) activate endogenous μ-opioid neurotrans- The nocebo effect is, by its nature, challenging to mission, while suggestions of a negative outcome study in a rigorous scientific setting. There are obvious (pain increase) activate CCK-A [cholecystokinin A] ethical concerns with deliberately placing suggestions and/or CCK-B receptors.8 of negative outcomes in patients’ heads. Nonetheless, there might be utility in studying which patient charac- Gastrointestinal effects can also be induced via teristics make them more susceptible to nocebo. nocebo. Myers et al found that simply mentioning pos- A study published in JAMA listed the following clinical sible gastrointestinal side effects “resulted in a sixfold risk factors for susceptibility to the nocebo effect13: increase (P < 0.001) in the number of subjects in these • the patient’s expectations of adverse effects at the centers withdrawing from the study because of sub- outset of treatment; jective, minor gastrointestinal symptoms.”9 A similar • a process of conditioning in which patients learn from nocebo response has been observed for muscle relax- previous experiences to associate taking medication ants.10 Researchers were able to cause (and measure) with somatic symptoms; a decrease in the bronchodilator effect of isoproterenol • certain psychological characteristics such as anxiety, simply by telling patients that it was a bronchoconstric- depression, and the tendency to somatize; and tor, rather than a bronchodilator.11 • situational and contextual factors. A 2009 systematic review of antimigraine medication Research into further such clinical models might clinical trials also showed the power of nocebo: allow physicians to better navigate encounters with nocebo effect–prone patients. It is the responsibility of all clinicians to be aware of this effect and to diminish it In addition, and most interestingly, the adverse events as much as possible in their medical practices. in the placebo arms corresponded to those of the We must grow to appreciate the tangible power that anti-migraine medication against which the placebo our words hold over our patients. The challenge we face was compared. For example, anorexia and memory is how to create a more positive-minded environment for difficulties, which are typical adverse events of anti- patients, while also remaining honest about their progno- convulsants, were present only in the placebo arm ses and the risks of the medical therapies we offer them. of these trials. These results suggest that the adverse Dr Agnihotri is a primary care physician with special interests in sports and exercise events in placebo arms of clinical trials of anti- medicine and occupational injuries practising in Calgary, Alta. migraine medications depend on the adverse events Competing interests None declared of the active medication against which the placebo is References compared. These findings are in accordance with the 1. Stathis P, Smpiliris M, Konitsiotis S, Mitsikostas DD. Nocebo as a potential con- expectation theory of placebo and nocebo effects.12 founding factor in clinical trials for Parkinson’s disease treatment: a meta-analysis.