Placebo Effect

1955

Henry K. Beecher (1904–1976)

One of the most studied medical and psychological phenomena of the twentieth century was the placebo effect. The word placebo comes from the Latin word meaning “to please.” It has been defined as any treatment that contains no known or proven active curative agent, such as a prescription pill that is in fact inert, though the patient has been told it will be effective. The beneficial effect of receiving the placebo appears to stem from the expectation of improvement. Placebo effects have been found in the treatment of a wide range of medical and psychological conditions. Modern researchers have concluded that such placebo effects are normal or typical responses to treatment.

Although the placebo effect must surely have existed for millennia, its documented history in Western medicine dates from the eighteenth century. During the nineteenth century, the placebo effect was widely acknowledged as part of the physician’s armamentarium. The diverse nostrums prescribed by itinerant healers, phrenologists, and snake-oil salesmen in rural and pioneer America presumably relied on a similar mechanism of treatment to achieve some beneficial results for the patients who used them.

The serious study of placebos and the placebo effect can be dated from the publication of physician Henry K. Beecher’s “The Powerful Placebo” in the Journal of the American Medical Association (1955). The paper stimulated research that pointed to a psychological role in health and illness—such as Hans Selye’s theory on Stress or the linkage of coronary heart disease to what came to be called the Type A Personality—and gave a new impetus to the study of mind-body connections in health and disease. The placebo effect is thought to be important enough to be a necessary part of randomized controlled trials of all new medications.

SEE ALSO Mind-Cure (1859), Psychosomatic Medicine (1939), Type A Personality (1959), Psychoneuroimmunology (1975), Biopsychosocial Model of Health (1977), Mind-Body Medicine (1993)

A portrait of Henry K. Beecher, 1955.

Two PET scans taken from a former opioid addict under the influence of morphine shows decreased brain activity (lighter tones) in the top scan as compared to activity in the same brain under the placebo (no drug) in the lower scan, 1980.