"No Better Than a Placebo" by Ted Kaptchuk (NYT 2023-10-10) explains some of the complex psycho-physical issues surrounding health:

To date, the best explanation for the results of open-placebo trials suggests that for certain illnesses in which the brain amplifies symptoms, engaging in a healing drama can nudge the brain to diminish the volume or false alarm of what’s called central sensitization — when the nervous system overemphasizes or amplifies perceptions of discomfort. This mostly involves nonconscious brain processes that scientists call Bayesian brain, which describes how the brain modulates symptoms. The intensification and the relief of symptoms use the same neural pathways. Considerable evidence also shows that placebos, even when patients know they are taking them, trigger the release of neurotransmitters like endorphins and cannabinoids and engage specific regions of the brain to offer relief. Basically, the body has an internal pharmacy that relieves symptoms.

So placebos should be used – with full recognition of both their benefits and limitations: "[They] shouldn’t be a first-line treatment; patients should be given what effective medicines are available. After all, placebos rarely, if ever, change the underlying pathology or objectively measured signs of disease. I like to remind people that they don’t shrink tumors or cure infections."

Kaptchuk's bottom-line conclusion is a crucial one:

_{(cf Medicine and Statistics (2010-11-13), Dizzy Doc (2023-06-22), ...) - ^z - 2023-10-11}