How does the placebo effect work?
Yaroslav Ashikhmin, Post-science
A placebo is a substance with no obvious medicinal properties that can be used as a medicine or mask a medicine. The phenomenon of improvement due to the use of such a drug is called the placebo effect. This effect can be traced in a number of mental illnesses, pain syndrome, bronchial asthma, Parkinson's disease, irritable bowel syndrome, coronary heart disease and arterial hypertension.
The effect of using a placebo is not as reliable as the effect of using real drugs. Placebo due to the placebo effect can lead to some subjective improvement in the condition, but at the same time it rarely cures the disease. A person may feel an improvement in the condition, which is not related to the fact that the disease has "receded". For example, a patient may feel better against the background of the use of homeopathy, which acts precisely due to the placebo effect.
The history of the use of placebo in clinical medicine began a long time ago. For example, the famous doctor Matvey Mudrov, who lived in the XVIII–XIX centuries, used simple, gold and silver powders that relieved the pain of patients. It was only after the doctor's death that it became clear that the main component of these powders was ground chalk.
Today, placebo is used in different situations. First, placebo is used to relieve the patient's pain when effective drugs are not available. Secondly, it is prescribed for possible improvement of the condition when there is no confidence in the effectiveness of the existing medication. Thirdly, it is used unknowingly - for example, when a doctor prescribes a drug, being sure of its effectiveness, but the drug does not work. The third situation is the most dangerous, because seemingly safe drugs may have hidden side effects that are observed after a long time.
A large number of different neurophysiological mechanisms are involved in the implementation of the placebo effect: the endocannabinoid system, dopaminergic, endorphin systems. When using placebo, certain areas of the brain are activated: the prefrontal cortex, the anterior part of the cingulate gyrus (previously this area was designated as the "pleasure center"), the nucleus accumbens. A combination of mental and neurological mechanisms is involved. In this case, suggestion plays an important role. For example, in one study, patients with migraine were divided into two groups. One group was given a placebo, but they said it was a strong migraine drug – "Rizatriptan". Another group was given "Rizatriptan", a real remedy for headaches, but they said it was a placebo. There was no difference in efficiency. That is, the doctor's words about the patient receiving a strong medicine acted as effectively as "Rizatriptan" per se. But when patients were given "Rizatriptan" and told that it was "Rizatriptan", the effectiveness of the drug in the aspect of headache relief increased by 50%.
Interestingly, placebo is more effective when administered parenterally, for example through ivs. If the administration of the drug is sensitive for patients, then its effect is higher. The analgesic effect of a placebo for the same migraine is 7% higher if the doctor gives an injection, and does not offer the drug in tablet form. And the price of the drug also plays a role: if you tell the patient that the drug, which is actually a placebo, is more expensive, then it turns out to be more effective. Persuasion plays a very important role. In addition, even the presence of a psyche is not necessary for the placebo effect to work – there are a number of studies that have shown the effectiveness of placebo in animals.
A placebo can be comparable in effectiveness to a drug for diseases in which a decrease in the quality of life is primarily due to mental disorders and pain. But we must remember that such an improvement in physical condition is not always translated into an improvement in physiological parameters. For example, the placebo effect was manifested during the Second World War. When the drugs ran out, the shell-shocked soldiers were injected with saline under the guise of morphine, and this reduced the pain. But not always the mechanism of action of conditional saline has a purely psychological basis. For example, in a number of studies, scientists, in order to relieve pain, also brought saline, not analgesics, to the nerve fibers. It turned out that saline can somehow act on nerve fibers and also relieve pain. If the main purpose of using the drug is to relieve pain, a placebo can work and achieve the desired effect. But this effect will be less lasting than the real medicine. A placebo can be used to relieve pain, but it is extremely unlikely to cure diseases with a placebo. For example, homeopathy, which works only due to the placebo effect, helps to improve the psychological picture of the perception of the disease, but at the same time it does not get rid of the disease itself under any circumstances.
The use of homeopathy is a gross violation of bioethics in situations where there is a real medicine or when it is known for sure that a placebo is ineffective. In addition, it is forbidden to use homeopathy in the treatment of bacterial infections, heart diseases, rheumatological diseases, in which medications that work accurately are already known. In other words, if there are drugs with proven effectiveness, the use of homeopathy is criminal. But if there are no drugs with proven efficacy, as in the treatment of acute respiratory viral infections, the use of a placebo is acceptable.
In a recent interview, British scientists noted that an implicit placebo, that is, a placebo, which is prescribed when doctors doubt the effectiveness of the drug, was prescribed by about 97% of doctors, and a pure placebo, that is, the same conditional saline solution, was prescribed by 12% of British doctors. Pure placebo is even more popular among Russian doctors. This is due to the fact that people in Russia often believe that observation in the clinic must necessarily be associated with parenteral administration of medications. Therefore, in the Russian tradition, many patients are given ivs with saline, that is, with a pure placebo. When assessing the ethics of this event, it is necessary to take into account the cultural factor, because they really "help" a lot of people.
About the author:
Yaroslav Ashikhmin – Candidate of Medical Sciences, practicing cardiologist
Portal "Eternal youth" http://vechnayamolodost.ru
08.04.2016