An interesting read:
What if the Placebo Effect Isn’t a Trick?
New research is zeroing in on a biochemical basis for the placebo effect — possibly
opening a Pandora’s box for Western medicine.
https://www.nytimes.com/2018/11/07/magazine/placebo-effect-medicine.htmlnytimes said...
Kaptchuk had divided people with irritable bowel syndrome into three groups. In one, acupuncturists went through all the motions of treatment, but used a device that only appeared to insert a needle. Subjects in a second group also got sham acupuncture, but delivered with more elaborate doctor-patient interaction than the first group received. A third group was given no treatment at all. At the end of the trial, both treatment groups improved more than the no-treatment group, and the “high interaction” group did best of all.
The findings of the I.B.S. study were in keeping with a hypothesis Kaptchuk had formed over the years: that the placebo effect is a biological response to an act of caring; that somehow the encounter itself calls forth healing and that the more intense and focused it is, the more healing it evokes.
In the course of conducting the study, Kaptchuk had taken DNA samples from subjects in hopes of finding some molecular pattern among the responses. Of course, the genome is vast, and it was hard to know where to begin — until, she says, she and Kaptchuk attended a talk in which a colleague presented evidence that an enzyme called COMT affected people’s response to pain and painkillers. Levels of that enzyme, Hall already knew, were also correlated with Parkinson’s disease, depression and schizophrenia, and in clinical trials people with those conditions had shown a strong placebo response. When they heard that COMT was also correlated with pain response — another area with significant placebo effects — Hall recalls, “Ted and I looked at each other and were like: ‘That’s it! That’s it!’ ”
It is not possible to assay levels of COMT directly in a living brain, but there is a snippet of the genome called rs4680 that governs the production of the enzyme, and that varies from one person to another: One variant predicts low levels of COMT, while another predicts high levels. When Hall analyzed the I.B.S. patients’ DNA, she found a distinct trend. Those with the high-COMT variant had the weakest placebo responses, and those with the opposite variant had the strongest. These effects were compounded by the amount of interaction each patient got: For instance, low-COMT, high-interaction patients fared best of all, but the low-COMT subjects who were placed in the no-treatment group did worse than the other genotypes in that group. They were, in other words, more sensitive to the impact of the relationship with the healer.
The discovery of this genetic correlation to placebo response set Hall off on a continuing effort to identify the biochemical ensemble she calls the placebome — the term reflecting her belief that it will one day take its place among the other important “-omes” of medical science, from the genome to the microbiome. The rs4680 gene snippet is one of a group that governs the production of COMT, and COMT is one of a number of enzymes that determine levels of catecholamines, a group of brain chemicals that includes dopamine and epinephrine. (Low COMT tends to mean higher levels of dopamine, and vice versa.) Hall points out that the catecholamines are associated with stress, as well as with reward and good feeling, which bolsters the possibility that the placebome plays an important role in illness and health, especially in the chronic, stress-related conditions that are most susceptible to placebo effects.