Placebo effect
The placebo effect refers to the observable changes in behavior or health that occur when individuals respond to a placebo, a substance with no therapeutic effect. Traditionally, placebos are administered to a control group in clinical trials, providing a baseline to compare against the effects of a treatment being tested. While the classic definition compares the placebo group's responses to those receiving actual treatment, some researchers, like P. C. Getzsche, argue for a more nuanced understanding. They suggest that the true placebo effect should be determined by comparing responses between a group given a placebo and a completely untreated group.
Historically, the term "placebo," meaning "I shall please," was first used in medicine in the late 1700s to describe substances given for psychological comfort rather than cure. Over the years, the role of placebos has evolved, with modern practices revealing their potential to enhance treatment outcomes, particularly in managing pain and various conditions. The brain's release of neurotransmitters, such as cannabinoids and dopamine, is thought to play a significant role in this phenomenon. The use of placebos raises important questions about the ethics of their application and the nature of patient care, reflecting diverse perspectives on treatment efficacy and patient expectations.
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Subject Terms
Placebo effect
The perceived placebo effect is defined as the difference in response between the control subjects who receive a placebo as compared with the experimental subjects who receive the therapy being tested. This definition has been challenged, and the true placebo effect is defined as the difference in response between the control subjects treated with a placebo and the control subjects who are totally untreated.
TYPE OF PSYCHOLOGY: Psychological methodologies
Introduction
The term “placebo” is derived from a Latin term meaning “I shall please,” but it has come to mean a false substance. A placebo is generally given to the control group in a scientific experiment, while the independent variable (item being tested) is given to other experimental groups. The placebo effect is the response of the control group, any changes in behavior—usually measurable, observable, or reported improvements in behavior or health—brought about as a result of exposure to this false substance. Using a placebo controls for the expectations of the subjects, in that neither the experimental subjects nor the control subjects know what to expect. If the subjects do not know whether they are in the experimental or control group but the experimenter does, this is known as a single-blind study. If neither the subjects nor the experimenter knows which group is the experimental one and which is the control, this is known as a double-blind study. A double-blind study controls for both experimenter bias and subject expectations.
History
The placebo was first used in medicine in the late 1700s, when a placebo was considered any substance (false medicine) given to a patient to please or satisfy him or her, rather than to treat or cure the patient's symptoms. Through 1950, it was felt that the placebo could provide psychological comfort to the patient while doing no harm physiologically. In 1961, the term “nocebo” was coined to refer to the negative side effects that might be associated with the administration of a false substance.
By 1940, the placebo had also become a substance given to the control group in experiments to deal with subjects' expectations. In 1955, a seminal paper was written by Henry K. Beecher, Henry K. Beecher dealing with “the powerful placebo effect.” In this paper, Beecher attempted to define and quantify the placebo effect on the basis of past research studies. Beecher used the term “placebo effect” to contrast with the effect that the independent variable had on the experimental group. Thus, the placebo effect was defined as the effect felt by the control group as compared with the effect felt by the experimental subjects.
Changes
This commonly accepted definition was challenged by P. C. Getzsche in 1994. He contended that the placebo effect did not look at the difference between an experimental group exposed to an independent variable and a control group exposed to a placebo. Instead, he saw the placebo effect as the difference between the control group that was given a placebo, and a control group that had nothing done to it. Getzsche thus indicated that the placebo effect was the change in the subjects' response due to the administration of the false substance. This implies that the placebo effect actually refers to the difference between the response of the untreated control group versus the control group treated with a placebo, rather than the difference between the experimental group and the control group treated with a placebo. This distinction has now come to be referred to as the true placebo effect as compared with the perceived placebo effect.
In the twenty-first century, physicians rely on placebos to help reduce pain in their patients. Although placebos do not have any effect on the conditions being treated, they still manage to have a positive result in patients. For example, experiments have shown that drugs meant to treat conditions like migraine, Parkinson’s disease, and irritable bowel syndrome have helped patients and improved their conditions. Adding placebos to these drugs, however, has worked even better. One explanation for this is that the brain releases neurotransmitters like cannabinoids and dopamine that lessen the patient’s pain perception.
- Key Concepts
- Control group
- Double-blind study
- Experimenter bias
- Nocebo
- Single-blind study
Bibliography
Beecher, H. K. “The Powerful Placebo.” Journal of the American Medical Association, vol. 159, 1955, pp. 1602–1606.
DeCraen, A. J., T. J. Kaptchuk, J. G. Tijssen, and J. Kleijnen. “Placebos and Placebo Effects in Medicine: Historical Overview.” Journal of the Royal Society of Medicine, vol. 92, 1999, pp. 511–515.
Ernst, E., and K. L. Resch. “Concept of True and Perceived Placebo Effects.” British Medical Journal, vol. 311, 1995, pp. 551–553.
Evans, D. Placebo Effect: Mind Over Matter in Modern Medicine. Oxford University Press, 2003.
Getzsche, P. C. “Is There Logic in the Placebo?” Lancet, vol. 344, 1994, pp. 925–926.
Kienle, G. S., and H. Kiene. “The Powerful Placebo Effect: Fact or Fiction?” Journal of Clinical Epidemiology, vol. 50, 1997, pp. 1311–1318.
LeWine, Howard E., reviewer. "The Power of the Placebo Effect." Harvard Health Publishing, Harvard Medical School, 22 July 2024, www.health.harvard.edu/newsletter‗article/the-power-of-the-placebo-effect. Accessed 20 Nov. 2024.
Ofri, Danielle. “The Conversation Placebo.” The New York Times, 19 Jan. 2017, www.nytimes.com/2017/01/19/opinion/sunday/the-conversation-placebo.html. Accessed 20 Nov. 2024.
Peters, D. Understanding the Placebo Effect in Complementary Medicine: Theory, Practice, and Research. Churchill Livingstone, 2001.
"Placebo Effect." Better Health Channel, Victoria State Government, 23 July 2021, www.betterhealth.vic.gov.au/health/conditionsandtreatments/placebo-effect. Accessed 20 Nov. 2024.