Subjects were given a sugar pill.  They were told it was a sugar pill.  They were told that sugar pills are not medicine.  And yet they had better outcomes than the control group who were not treated at all.

Edzard Ernst, a professor of complementary medicine at the University of Exeter, says, “This is an elegant study which suggests that the ritual of giving a patient a remedy is clinically effective, even if that patient has been told that the remedy is a placebo.” Kaptchuk himself says, “I suspect that just performing “the ritual of medicine” could have activated or primed self-healing mechanisms.” And Amir Raz, a neuroscientist who studies placebos at McGill University, adds, “Scientific reports make it clear, even if strange and counterintuitive, that receiving – rather than the actual content of – medical treatment can trigger and propel a healing process.”

Notably, the patients (apparently even the control group) were told about the psychology of the placebo effect.

They told the patients that “placebo pills, something like sugar pills, have been shown in rigorous clinical testing to produce significant mind-body self-healing processes.” And they explained: that “the placebo effect is powerful; the body can automatically respond to taking placebo pills like Pavlov’s dogs who salivated when they heard a bell; a positive attitude helps but is not necessary; and taking the pills faithfully is critical.”

There are many caveats and open questions, the full article is worth a read.