Functional disorders are a thing, and placebo surgery for osteoarthritis of the knee works just as well as real surgery: https://www.nejm.org/doi/full/10.1056/N

Functional disorders are a thing, and placebo surgery for osteoarthritis of the knee works just as well as real surgery: https://www.nejm.org/doi/full/10.1056/NEJMoa013259 https://www.nejm.org/doi/full/10.1056/NEJMoa013259 I have heard psychedelics be described as the most effective placebo of all placebos.