The placebo effect, which greatly distorts drug trial results, is commonly associated with psychology. When a patient is undergoing experimental treatment, he or she is positive. High expectations cause certain parts of the brain to produce hormones, and temporary relief comes. But not all scientists agree with this explanation and see here an independent phenomenon, the secret of which has yet to be revealed.
Cocoa helped
At the St. Petersburg military hospital at the beginning of the 19th century, they decided to find out whether homeopathy was effective. The patients were divided into three groups. The first were given homeopathic treatment, the second were given real pills, the third just ate well, rested, took baths and pills with lactose and cocoa.
Surprisingly, positive dynamics was observed in the third group. As a result, homeopathy was banned in Russia for several years. This was the first experience in the country where a placebo tablet without an active ingredient was used to study the effectiveness of treatment.
Placebos (usually sugar) have been widely used to control scientific experiments since the 20th century. In the simplest case, the participants in the experiment are divided into two groups: some are actually treated, others take a placebo. A more accurate, objective result is obtained if neither patients nor researchers know who gets what. This is called a randomized double-blind clinical trial. It is now the gold standard for testing new drugs.
The problem, however, is that patients on placebo often recover or experience marked improvement. Such situations, called the placebo effect, were massively faced by American doctors in the middle of the last century during clinical trials of drugs.
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Measurement error
In many cases, the placebo effect is explained by distortions arising from the statistical processing of the results: regression to the mean, the Will Rogers phenomenon, the Simpson paradox.
Errors in assessing the condition also affect if they cannot be objectively measured. For example, this concerns pain. In such situations, surveys and questionnaires of patients are usually used. A person can embellish feelings or simply express inaccurately.
The final result is influenced by the conditions of the experiments: patients participate in them, the experiments take place in laboratories. In such an unnatural environment, people behave differently.
It cannot be discounted that a certain number of participants naturally recover during the experiment.
Nevertheless, some researchers admit that the placebo effect is real, even if the final result is cleared of all statistical errors, random interference, subjective factors. Now it is becoming the subject of independent research.
How the spirit affects the body
In general, the prevailing point of view in science is that the placebo effect is a kind of random factor that must be taken into account when assessing the final test result.
There are several hypotheses on this score. It is believed that the nature of the placebo effect may be psychological, neurophysiological, genetic, or experience-dependent when conditioned reflexes come into play. The person knows that the pills will help, because he has been treated with them many times. When given a placebo in the form of a round white pill, he automatically reports an improvement in well-being, even if nothing has changed in his physiology.
Studies of brain activity during clinical trials have shown that the placebo effect appears there as well. An article by researchers from the United States, published in Nature Communications, shows the results of a follow-up of 63 patients who came to the clinic to be treated for chronic pain.
Some were given pain relievers, others a placebo. All had MRI and functional MRI. Subjects were required to record their symptom levels on a mobile app and verbally. It turned out that several parts of the brain tend to respond to placebo. Thus, the authors of the work argue, it is possible to predict which patients will show the placebo effect.
Scientists believe that mental attitude affects the brain and causes it to produce various neurotransmitters, which, in turn, give signals to the organs of the body and affect the physical condition. These are all speculations, the exact mechanism is unknown.
The placebo effect is not observed in all diseases / Illustration by RIA Novosti.
"Honest" placebo
The most famous researcher of the placebo effect is Ted Kapchuk of Harvard University School of Medicine (USA), who received a degree in Chinese medicine from Macau.
He is not satisfied with any of the mainstream explanations. In his opinion, the placebo effect may turn out to be something unique; completely new approaches will be needed to study it. However, he does not deny that this phenomenon is just "noise" that has not yet been cut off in the course of experiments.
Kapchuk and colleagues conducted three randomized clinical trials to study the placebo effect. In contrast to the standard protocol, he informed the participants that they were taking a dummy, explaining to them the essence of the placebo, why they should not wait for miracles.
His experiments involved patients treated with irritable bowel syndrome, chronic back pain and fatigue caused by long-term cancer therapy. There was a marked placebo effect everywhere.
Kapchuk admits that the placebo, provided the patient is informed about it, can be used in routine medical practice. However, he warns that this phenomenon must first be carefully investigated, and his experiments must be repeated by independent scientific groups.
In 2003 and 2010, volunteers from the Cochrane Collaboration, an evidence-based medicine organization, examined the results of many clinical trials on the treatment of pain, tobacco addiction, dementia, depression, obesity, nausea, analyzed all the data using meta-analysis and found no significant placebo effect. Both reviews are published in the Cochrane Library.
Tatiana Pichugina