According to a USCCB press release, the guidelines describe Reiki as a healing technique "invented in Japan in the late 1800s by Mikao Usui, who was studying Buddhist texts."
It characterizes Reiki therapy as teaching that illness is caused by "some kind of disruption or imbalance in one's 'life energy.'"
A Reiki practitioner is believed to be able to effect healing by placing his or her hands in certain positions on a patient's body to "facilitate the flow of Reiki, the 'universal life energy,' from the Reiki practitioner to the patient."
"Reiki lacks scientific credibility," the U.S. bishops' guidelines state, adding that scientific and medical communities have not accepted it as "an effective therapy."
"Reputable scientific studies attesting to the efficacy of Reiki are lacking, as is a plausible scientific explanation as to how it could possibly be efficacious," the bishops' guidelines add.
Reiki has many of the same problems as ceremonial magick in terms of being subject to scientific evaluation. The practitioner is such an important variable that repeatable experiments are difficult to set up and most of the healing effect is based on probability shifts. So in order to really do a good scientific study you need an enormous sample set to determine whether or not the practice is working.
Studies like this have been done with acupuncture, but they have taken many years to do. I remember some of those going on it the late 1980's when I was in college. One of my classes was on psychoneuroimmunology, and some of what it covered included attempts by neuroscientists to figure out what acupuncture was and how it worked. The most recent studies have shown a significant difference between subjects treated with needles and those who received no treatment, but there is little difference between groups in terms of whether or not the needles are placed in the "appropriate" locations for specific illnesses. Even after all these years, accupuncture looks like it's doing "something", but scientists still aren't quite sure what.
Even though such a study of Reiki would be similarly difficult, it's kind of interesting seeing this scientific criticism coming from the Catholic Church. To be fair, the Catholics come out in favor of mainstream science at least as much as other churches do if not moreso, as in the debate over creationism in which the Roman Catholic Church sided with the scientific community even though it was originally a Catholic who came up with the 6000-year-old Earth model that modern creationists support. But doesn't the Catholic Church also teach that you can be healed by prayer? What makes Reiki different?
Examining descriptions of Reiki as a "spiritual" kind of healing, the guidelines say there is a radical difference between Reiki therapy and healing by divine power.
"For Christians the access to divine healing is by prayer to Christ as Lord and Savior, while the essence of Reiki is not a prayer but a technique that is passed down from the 'Reiki Master' to the pupil, a technique that once mastered will reliably produce the anticipated results."
Shorter Catholic Church:
(1) Magick is okay as long as it's our magick, but otherwise it's bad.
(2) If magick works you shouldn't use it.
As a magician neither of those arguments makes very much sense to me. As far as (1) goes, many religious systems try to monopolize the magick use of their followers according to what they believe is the only "correct" or "authorized" system and the Roman Catholic Church has a particularly long history of doing just that going back over a thousand years. However, the universality of magical practices across different spiritual traditions would seem to imply that regardless of what any particular groups says, there are a lot of ways to make magick work.
I find (2) even more incomprehensible - it sounds as if the Roman Catholic Church is implying that you shouldn't make use of any magical practice that works well. I suppose this may just be an extension of (1) in that functional magick that doesn't fit the Catholic paradigm could undermine their monopoly on the "proper" use of magical powers.