The placebo effect causes all sorts of problems for drug trials in certain areas where the control arm does much better than expected swamping the statistics of the treatment arm (trials are powered with an assumption of how well the placebo will work).

Interestingly, the unexpectly effective placebo effect seems to be limited to the USA. Why nobody is sure.

I don't think you could publish a clinical trial that does not already consider the placebo effect, so it's unlikely these findings are related to it.

This focused mostly on cancer where the placebo effect doesn’t impact things like tumor size or survival.