placebo

medicine

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Placebo refers to tablets, pills and injections that have no therapeutic effect. It can replace and comfort people who take certain drugs for a long time and cause adverse consequences. It has no therapeutic effect. But because patient It can relieve pain by trusting doctors, calling patients self suggestion, and expecting the efficacy of certain drugs Tremor Or relieving symptoms. stay clinical medicine In order to observe the efficacy of a certain drug Control test 。^[1]

Drug name: placebo^[2]
Foreign name: Placebo
Alias: fake medicine
Prescription medicine or not: no

Dosage form: Tablets or injections
Careful use by athletes: yes
Whether included in medical insurance: no
Drug type: chemical
Scope of influence: blood pressure 、 heart rate , gastric secretion vomit etc.

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definition

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Placebo is a "simulated drug". Its physical characteristics, such as appearance, size, color, dosage form, weight, taste and smell, should be as same as the test drug as possible, but should not contain the active ingredients of the test drug (such as lactose or starch Tablets or normal saline Injections).^[3]

Drug action

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It has certain effect on psychological factor Participating in control autonomic nervous system Functions such as blood pressure, heart rate, gastric secretion, vomiting, and sexual function have a greater impact.

1、 It can stabilize the patient's tension.

2、 It is used as a blank control of the experiment during the research and development of new drugs to exclude the placebo effect that may be caused by new drugs.

3、 It is used to relieve the pain of patients with advanced cancer.

Drug effect

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The effect of placebo is called "placebo effect".

According to literature reports, patients are treated by highly trusted doctors gastroduodenal ulcer The short-term curative effect of can reach about 70%. yes Malignant tumor For patients, placebo will produce a "placebo effect" to alleviate some symptoms, but it is ineffective in delaying life.^[4]

This discovery has brought a new possibility to the existing medical methods: use the placebo effect to enhance the effect of conventional therapy. Scientists are studying how to maximize the efficacy of conventional treatment through the placebo effect. Some studies have shown that the dosage and appearance of the placebo are very important. The injection seems to be more effective than the internal medication, but the most important thing is the attitude of the doctor.

University of Southampton The researchers of. They randomly selected two groups of patients. One group of patients was diagnosed by the doctor and told that they would get better soon - some did not receive any treatment; The other group of patients were given vague diagnosis, and there was no guarantee that they would recover quickly. Results 64% of the patients in the first group improved, while only 39% in the second group. This shows that the attitude of doctors is far more important than their prescriptions when treating patients. If the placebo effect can be combined with conventional treatment, it will make great changes in existing medical methods. Benedetti said: "If we can make full use of the placebo effect, let the patients take the medicine on Monday, take the placebo on Tuesday, and then take the medicine on Wednesday. In this way, we can reduce the drug use by 50%."

Explanation of terms

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explain

Placebo, which is made of substances without efficacy and toxic side effects, such as glucose , starch, etc., the shape is similar to the real medicine. Taking placebo can produce a good positive psychological response to patients who are eager for treatment and have full trust in medical staff, thus improving people's physiological state and achieving the desired efficacy. This response is called placebo effect.

Another meaning of placebo is to describe the methods and measures that can produce psychological soothing effect. For example, Beijing has introduced a new house purchase contract, but some lawyers and community governance experts believe that some terms are "placebo".

Produce effect

First of all, patients' psychology of expecting drugs to work stimulates physiological reactions; Secondly, patients have physiological conditioned reflex to their medical environment.

Enigma of effect

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As early as hundreds of years ago, doctors realized the powerful role of placebo. When a patient takes or receives drugs or therapies that have no pharmacological effect and no side effects, so as to improve his condition, it is called placebo effect in medicine. In clinical diagnosis and treatment, this non-toxic side effect substitute has played a positive role in curing patients. But how big is the placebo effect? How does it work? These problems are still unsolvable mysteries lingering in people's minds. Some people say that placebo can affect about 1/3 of patients. In fact, this ratio is not static. For patients with Mental depression For 80% of patients, the effectiveness rate of placebo is as high as 80%, while for patients with diabetes and other cases, its effect may be zero.

Spiritual function

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To solve the puzzle of placebo effect, let's first do a simple experiment: comparison sedative and analeptic The effect of. The researchers invited 60 volunteers to participate in the experiment and prepared two drugs for them: the blue pills are sedatives, and the red ones are stimulants. Participants were randomly given a drug to take, and then observed for signs of drowsiness. The results are obvious: people taking sedatives are more likely to have the above symptoms than those taking stimulants, and the proportion is twice that of the latter. This seemed normal - until the answer was revealed: the volunteers had neither taken sedatives nor stimulants. They are taking the same compound with no pharmacological effect and no toxic side effects, the only difference is the color of the tablet.

This experiment fully demonstrates that spirit Great influence on the body. In the past few years, scientists have proved the effect of placebo through a variety of similar experiments - as long as we believe that a certain treatment can produce effects, we can make patients better. Experiments have proved that placebo has the most obvious effect on patients with mental depression or pain. This harmless treatment usually has the same effect as "real" drug treatment.

Huge controversy

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How effective is the placebo? How does it work? Can it be used to improve the treatment of patients? These problems have caused great controversy in the medical field. From the perspective of ethics, it is generally considered immoral to use placebo as a substitute for conventional treatment. But this is only a modern view. Until the beginning of the 20th century, doctors often gave patients pills made of dough and injections made of injection water, in order to make them believe that their disease could get better. The effect of placebo completely depends on the psychological state of the patient, and the effect is best for people who are simple minded or easily neurotic. However, in the middle of the 20th century, with the increasingly rigorous attitude of medical treatment, people's views on placebo also gradually changed. Many people believe that placebos can only be used in clinical trials to control experiments or test the effectiveness of a treatment method that has not yet been promoted. They believe that it is immoral to apply placebo in clinical treatment, and only the treatment method with far better effect than placebo is medically acceptable. But just like the experiment mentioned in the article, the researchers were surprised to find that sometimes just using the placebo can make the patient's condition greatly improved. In 1955, American scientist Henry Beecher published the landmark paper "Powerful Placebo". This paper analyzes the clinical experiment results of 15 kinds of placebos, and concludes that in general, 35% of patients can be effectively improved after using placebos.

That means that 1/3 of people can use no medicine and only rely on the placebo to treat the disease. But Beecher made a fatal mistake in his analysis: he assumed that the placebo effect was the only explanation for the improvement of the patient's condition. In fact, there are countless possible explanations for the improvement of the patient's condition or symptoms. Many diseases (such as back pain) have the characteristic of "self-healing", which means that they will recover gradually. Hull University Experts studying placebo Owen· Kirsch said: "It is wrong that 1/3 of people can rely on placebo to treat diseases." What is the real situation after all? In 2001, University of Copenhagen Two researchers from. They analyzed the results of hundreds of clinical trials and compared the effects of drug treatment, no treatment and placebo treatment. If there is a so-called "placebo effect", then patients who use placebo should be better than those who do not receive any treatment.

Their discovery is still controversial today. By comparison, the two researchers found that placebo was almost useless in clinical treatment. In addition to some insignificant effects such as pain relief, the effect of placebo treatment is almost the same as that of no treatment. There are also some researchers who insist on their own view that the conclusions reached in the paper are not credible. Most critics believe that the placebo effect cannot be generalized. Kirsch pointed out: "It seems more reasonable to study the effect of a specific treatment method on a certain disease. The placebo effect is quite obvious on symptoms such as mental depression, and can also have effect on symptoms such as pain, but the effect is relatively weak, and may not have effect on diseases such as diabetes."

While debating whether placebo has "curative effect", some scientists also study how the placebo effect affects the human body. In an experiment, the University of Turin released Riccio ·Benedetti and colleagues injected volunteers with capsaicin to make them feel pain, and then applied them with a powerful painkiller. In fact, this painkiller does not contain any medicine at all, but the volunteers generally feel the pain has been reduced. The researchers then injected them with naloxone, a powerful anti anesthetic, and the pain returned. Through this experiment, the researchers concluded that the placebo effect is not purely psychological, and the psychology of patients expecting drugs to work can also cause physiological Conditioned reflex 。 In this experiment, the placebo stimulated the brain to secrete pain relieving chemicals.

Counterfeit stimulant

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Research shows that placebo can activate the endogenous analgesic component of the body - opioid substances. In particular, if a person has received morphine injection and formed the association between drug injection and pain relief, then injecting him with normal saline can also relieve his pain. In this case, can this method improve athletes' pain tolerance in sports competitions?

World Anti Doping Organization banned medicine It is specified in the table that morphine It is illegal, but it can be used during training. Therefore, athletes can inject morphine before competition and then use placebo during competition. However, in order to ensure the effectiveness of this strategy, athletes need to stop injecting morphine a few days before the game to ensure that morphine will not remain in the body on the day of the game. However, it was not until the researchers determined that the conditioned reflex was still effective after a longer interval of more than one day.^[5]

Scientific research application

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Any drug can produce placebo effect, no matter good effect or bad effect. To determine a Drug action Yes No Placebo effect , placebo should be used in scientific research contrast Half of the subjects were given the test drug and half were given the placebo. Ideally, neither the medical staff nor the patients knew the difference between the test drug and the placebo. This is Double blind method 。 At the end of the test, compare the effects of the two preparations and remove the influence of the placebo to determine whether the efficacy of the tested drug is reliable. Such as studying a new Antiangina drugs 50% of those taking placebo % The results show that the efficacy of this new drug is questionable.^[6]

Therapeutic application

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Any treatment has a placebo effect. If patients have confidence in medical staff and drugs, the placebo effect is obvious; For treatment negative , it will affect its curative effect, and even Adverse reactions 。 If both doctors and patients believe that placebo is beneficial joint Nontherapeutic Vitamin B12 The treatment of arthritis can alleviate symptoms. Sometimes a low activity Sexual drug It can also produce obvious curative effect.

In addition to scientific research drugs, doctors should avoid deliberately choosing placebo. Because such deception can damage the relationship between doctors and patients. In addition, doctors may misunderstand the symptoms of patients and cover up the real condition. When other medical staff participate in the diagnosis and treatment at the same time, this deception will increase the patient's distrust. However, doctors can Chronic pain 's patients Yes Analgesics Try placebo after dependence.

Although doctors rarely use placebos, most doctors believe that placebos can prevent or alleviate patients disease Although there is no scientific basis for its role. For example, long-term use Vitamin B12 Or others vitamin The symptoms of disease occurred after discontinuation of use; The pain of the patient was significantly relieved after use. Due to the different cultural and psychological functions, some people can benefit from this seemingly unscientific treatment. Many doctors believe that this treatment method is not good for the relationship between doctors and patients, and is not good for medication, but most doctors still believe that some patients placebo effect Obviously, after drug withdrawal Unfavorable 。^[6]

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