Overview：The placebo effect, also known as the counterfeit drug effect, the counterfeit drug effect, and the surrogate effect (English: Placebo Effect, derived from the Latin placebo, meaning "I am willing", understood as "I will be comforted") refers to the fact that the patient receives Ineffective treatment, but "anticipate" or "believe" that the treatment is effective, and the symptoms of the patient are relieved. Some people think this is a noteworthy human psycho-physiological response, but others think it is an illusion produced by the design of medical experiments. Whether this phenomenon really exists, scientists have yet to fully understand.
The placebo effect was proposed by Dr. Henry K. Beecher in 1955, and it is also understood as "non-specific effects" (non-specific effects) or subject expected effects.
A completely opposite effect also exists at the same time-Nocebo effect: The patient does not believe that the treatment is effective, and may worsen the condition. The nocebo effect (the Latin nocebo means "I will be hurt") can be detected using the same method as the placebo effect. For example, a group of control groups taking ineffective drugs will experience deterioration in their condition. This phenomenon is believed to be due to the negative attitude of the recipients of the drug to the efficacy of the drug, which offsets the placebo effect and has the nocebo effect. This effect is not caused by the drugs taken, but based on the patient's psychological expectations for recovery.
Control study：There are reports that about a quarter of patients taking placebos, such as placebos that claim to be able to treat back pain, indicate that the pain is relieved. What's striking is that the relief of these pains is not only dependent on patients' reports, but can be detected by objective methods. This improvement in pain did not occur in patients who did not receive a placebo.
Because of the discovery of this effect, government regulatory agencies have stipulated that new drugs must pass clinical placebo-controlled tests before they can be approved. The test result must not only prove that the patient is responsive to the drug, but also that the test result must be compared with a control group taking a placebo to prove that the drug is more effective than the placebo ("effective" refers to the following 2 items or one of them: 1 ) The drug can affect more patients than placebo, 2) Patients have a stronger response to the drug than placebo). Since the doctor's perception of the practicality of the treatment will affect its performance, it can also affect the patient's perception of the treatment. Therefore, the drug test must be performed in a double-blind manner: neither the doctor nor the patient knows whether the drug is a placebo.
Recently, it has also been discovered that a similar phenomenon occurs in simulated surgery. Therefore, some surgical techniques must be subjected to placebo-controlled studies (a double-blind method is rarely used, for obvious reasons). In order to support testing, the drug test group will be treated better than the placebo control group.
Almost all studies conducted in this controlled manner show that placebo pairs can improve the condition. Example: Kahn published a meta-analysis on anti-anxiety drugs and found that suicide or suicide attempts in the group taking placebo dropped by 30%, while the group taking anti-anxiety drugs It is down 40%.
However, general research projects do not add a group that does not receive any treatment as a control, so it is difficult to calculate the actual degree of influence of the placebo effect.
The "placebo effect" and "nocebo effect" have been put forward for more than 50 years, but they still clearly appear in experimental medical situations. The existence of this effect means that trust between people is very important in the relationship between doctors and patients. Therefore, "humanity care" must not be absent from medical and patient communication, and the medical ecology should carefully manage a "trust and peace of mind" area.
Responders：People who are prone to corresponding psychological and physical effects when using a placebo are called placebo responders. The personality characteristics of this kind of person are: good communication, dependence, susceptibility to hints, lack of self-confidence, good attention to their various physiological changes and discomfort, suspiciousness and neuroticism.
We should remember that the placebo effect is more likely to occur in patients. Approximately 35% of patients with physical illness and 40% of patients with mental illness will have this effect. It is precisely because of the psychological characteristics of patients that quack doctors and witch doctors can have an active market and perform their skills.
Principle of action：There are two assumptions about how placebo works: Subject-expectancy effect and conditioning.
Expected effect
The subject expectation effect leads the patient to consciously or unconsciously report the improvement of the condition, thus leading to the appearance of the placebo effect. In the article, Asbjørn Hróbjartsson and Peter C. Götzsche questioned that “most patients politely tend to report improvement in order to cater to the experimenter, even if they do not feel improved.” Subjective prejudice may also make patients subconsciously believe that their condition is due to Improve with attention and care.
Restrict response
Classical restraint is an association learning model that enables trainees to learn to make specific responses in specific situations. A well-known example is Pavlov’s dog experiment: every time a dog is given food, the bell sounds Associated with food. Therefore, the placebo causes the patient to produce a biological response similar to the effective drug, which may be caused by restriction.
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