[fooblat]

I find those studies problematic. In the ones I read from your links, the doctor says something along the lines of "this pill is a placebo. It means it has no active ingredients. However, the 'placebo effect' is known to be powerful and if you take these pills as instructed they can still help you..."

As I understand it, a big part of the placebo effect is setting the expectation that the treatment will help. And it is only known to help in subjective conditions, such as pain.

I expect we might see different results if the doctor said something more like "This pill has no active ingredients and does nothing. We are giving it to you to see if you will imagine that it worked anyway."

Kissing a child's scraped knee is not a treatment but, it along with a reassuring "there, all better!" works wonders for the child anyway. They are comforted and relived.