The placebo effect depends on genetics
Last reviewed: 16.10.2021
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Scientists from the Harvard Medical School and the Beth Israel Deaconess Center concluded that the placebo effect acts on people who have a certain genetic sequence.
Experts studied the effect of the placebo effect in people with different variants of the COMT gene, which encodes the protein cotechol-O-methyltransferase, which is a participant in the catabolism of dopamine, a neurotransmitter responsible for the sense of pleasure.
Participants in the study were 104 people who suffered from irritable bowel syndrome, in which the patient feels chronic pain in the abdominal region, discomfort and bloating. All subjects were divided into three groups, and selection was made randomly.
Two groups of participants received treatment by placebo-acupuncture (the needles did not enter the skin), and the third group received no treatment at all.
Volunteers from the first group underwent therapy in the usual setting, and with the participants of the second group the doctors maintained friendly, warm relations. A month after the start of the study, participants were asked to describe their condition and state of health. Blood samples of all volunteers were also taken for analysis.
Scientists found that those people who were carriers of two alleles of the COMT gene with methionine at 158 positions, felt a significant improvement in the condition, and therefore were the most susceptible to placebo. In those participants who in one of the alleles of methionine was replaced by valine, there were also improvements, but not so pronounced. There were no changes in patients bearing two alleles with valine at 158 positions.
As scientists assumed, the success of the placebo effect also depended on the trusting relationship between the physician and the patient. Volunteers from the second group showed the highest result, because they had good relations with the doctors, they were cared for and supported, which influenced the final result.
However, despite the success of the research, experts say the need for further studies of the placebo effect and genetic predisposition. In the near future, experts plan to conduct similar experiments on patients with other types of diseases.