Explaining and Exploiting Placebo Effects

EXPLAINING AND EXPLOITING PLACEBO EFFECTS HENRY BYERLY, Ph.D.* The word "placebo" has a long history in English. The term, which means "I shall please" in Latin, was introduced into ecclesiastical English in the twelfth century from its use in the first verse of the Vulgate Psalm 114. The first appearance in medical literature was in the 1811 edition of Hooper's Medical Dictionary, where "placebo" is defined as "an epithet given to any medicine adapted more to please than benefit the patient." The phrase "placebo effect" is of more recent origin. On the face of it the phrase is an oxymoron: an inefficacious substance that yet has effects . A typical definition in contemporary medical literature is: "Any change in a patient's symptoms that is the result of the therapeutic intent and not the specific physicochemical nature of a medical procedure" [1, p. 761]. In the folklore of medicine no substance has been too quaint, no concoction too vile to be employed, and employed successfully, to relieve complaints. It has often seemed convenient to appeal to the blanket notion of placebo effects in trying to account for the apparent effectiveness of "irrational" therapeutics. Can we, however, distinguish so easily which therapeutics are irrational? Until very recently most medical authorities in the West lumped acupuncture with voodoo and blood letting , but acupuncture has now gained a measure of respectability. Does it have genuine efficacy over and above placebo effects? Viewing surgery using acupuncture as the only anesthetic must be impressive, but it should be noted that studies show that placebo saline injections can compete well with morphine in relieving severe pain in some 40 percent of cases [2]. Understanding placebo effects is especially important today when the general public has become increasingly aware of controversies over medical treatment. For example, the health food craze for extra doses of vitamins and minerals now supports a sizable industry despite the cool reception by most of the medical establishment. Linus Pauling's advocacy of large doses of vitamin C for preventing and curing colds is shared by millions against the advice of most physicians [3]. Pauling [4] has also engaged in a bitter dispute with psychiatrists over the efficacy of niacin in megavitamin therapy for schizophrenia. *Department of Philosophy, University of Arizona, Tucson, Arizona 85721. Perspectives in Biology and Medicine · Spring 1976 \ 423 Although placebo effects have been exploited, directly or indirectly, in relieving afflictions from time immemorial, the placebo effect is not sufficiently understood for physicians to exercise more than vague, uncertain control over it. The placebo effect was little discussed in medical literature until quite recently. Up to 1950 there were only a dozen or so articles on the subject, but today the total numbers into the hundreds. The concept "placebo effect" implies that there are placebo causes, but as one investigator candidly remarked: "The etiology of the placebo effect is not yet understood" [5, p. 712]. In more colorful language, another writer concedes that "the nature of the neural alchemy that enables the credulous mind to transmute illusion into reality remains very largely obscure" [6, p. 70], Placebos seem to work like magic incantations in that both require an "object" of concentration, and virtually anything can function as that object. The fact that placebos commonly yield between 20 and 70 percent relief of symptoms in controlled tests rules out simple, straightforward testing of a drug's effectiveness. Even those drugs whose efficacy is hardly questioned sometimes compete with difficulty against placebo effects. The analgesic effects of aspirin, for example, seem to vary from study to study [7]. Some studies fail to show a significant effect of aspirin over placebos for relieving symptoms of rheumatoid arthritis [8]. Furthermore , many of those suffering from arthritis who failed to get relief from lactose tablets did show improvement when injected with saline solution. The relief in question was not merely in subjective judgments of how patients felt but included objective improvement in swelling. Placebos mimic most of the effects of drugs. Patients can become addicted to them. Some subjects have required hospitalization from placebo side effects. Placebo effects are most commonly interpreted as psychological in origin, or in the vernacular, "it's all in...