It's ALL "placebo effect" when it comes down to it. All experience is contained within and is projected outwards. Oh and it's all the same projector fragmented into many lenses.
Some people call this god or one.
I liken healing to the story of the boy who regrew a limb because noone told him he couldn't. Our accepted constructs are what determines what we can or cannot do. It's all in us....all potential to create. The outer is but a projection of what lies within. This is affected by a collective agreement if you like, that we subscribe to (buy into with our belief systems).
What you refer to as placebo effect is occuring when yogis use their intent to control their heart rate. It is at work when humans perform incredible feats. When the 4 minute mile was finally broken, many other's also crossed that same threshold the same year. We block or allow with our mind (beliefs). Placebo is the essence or potential for creation of all possibilities out of thought (consciousness). It is our true spiritual nature beyond the secondary physical aspect of our creation. Much of our science it trying to measure relationships within this secondary aspect of cosnciousness (projected "physical" world). This is mechanistic science and is illusive. The greater science is stemming out of quantum physics and into consciounsess (noetic science).