Psychosomatic issues, while ‘in someone’s head’ cause very real physical problems that are quite measurable. Our brain and our bodies are tied together in ways that are not convenient to think about, frankly.
Just like the placebo effect causes real, very significant healing effects, even a subconscious association with a place as ‘bad’ causes real, very significant detrimental effects that are externally measurable.
Essentially believing you have been given something that will make you healthier, can reduce the stress responses, pain perception and other issues that may be making the problem worse. In some cases it can be enough to allow the immune system to get better traction and objectively get healthier faster than with no medicine.
The wild part is that the body releases internal painkillers when they get some fake (or real) ones, and that this reaction can be blocked by naloxone, indicating that it's a physical response.
No, the mind can have a significant effect on the body. For example this webmd article on placebo cites studies where what the participant was told about a pill (stimulant vs sleep aid) effected heart rate, blood pressure and reaction time in opposite directions. https://www.webmd.com/pain-management/what-is-the-placebo-ef...
Nah, it works the other direction too. People expecting side effects from a placebo often get them- though you could argue that many side effects are common symptome now being associated with the drug. Still, the placebo effect beats no treatment per https://ebmh.bmj.com/content/5/1/15 or https://pubmed.ncbi.nlm.nih.gov/12535498/
It isn't. People recover better with a placebo than with nothing. There are studies that even show that some placebo are better than other based on the price, the colour, who prescribed it, ...
