To the extent that Reiki or any other alternative medicine technique actually does anything, it's easily explainable by the placebo effect.
You know what we call alternative medicine that works? Medicine.
You know what we call alternative medicine that works? Medicine.
But anyway, well, see, there you go. Meaning no disrespect, my whole point is that you and others like you cannot or will not "see" this thing, yet it's definitely "there".
I think it's got to be the "social side of science" somehow preventing otherwise-rational minds from seeing what's right in front of them (even during a scientific study of Reiki.)
I don't need either the placebo effect, nor mystical energy to explain Reiki. Ditto for most alternative medicines I've seen friends swear by.
It's all Descartes fault, essentially, by postulating the "mind" as distinct from matter.
More specifically, placebo pain-relief has been associated with endogenously produced opioids for approximately 40 years now (1978, I believe).
More recent research suggests that much of the variance in the effects of pain-killers can be associated with these endogenously produced opioids (when the patient was not aware of the pain-relief, responses were similar).
So essentially, the placebo effect is just a normal part of your body responding to medical treatment, regardless of the efficacy of said treatment.
I'm talking about pain because most of the research is on pain, but the principles are similar where placebos tend to be effective (not against infections, sadly but pain and depression seem to be extremely placebo-responsive).