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This study reviews the available clinical studies of Reiki to determine whether there is evidence for Reiki providing more than just a placebo effect. The available English-language literature of Reiki was reviewed, specifically for peer-reviewed clinical studies with more than 20 participants in the Reiki treatment arm, controlling for a placebo effect. Of the 13 suitable studies, 8 demonstrated Reiki being more effective than placebo, 4 found no difference but had questionable statistical resolving power, and only one provided clear evidence for not providing benefit. Viewed collectively, these studies provide reasonably strong support for Reiki being more effective than placebo. From the information currently available, Reiki is a safe and gentle “complementary” therapy that activates the parasympathetic nervous system to heal body and mind. It has potential for broader use in management of chronic health conditions, and possibly in postoperative recovery. Research is needed to optimize the delivery of Reiki.

Reiki is one of the more popular complementary modalities used by Australians to manage their health conditions, There is little data available on how widely Reiki is used in Australia, but information gleaned from public sources indicates that it is being employed with good effect in some hospitals, cancer support centers, drug and alcohol rehabilitation centers, and in palliative care. At the Oncology-Haematology Unit at Bega Valley Health Services, Reiki sessions are provided by Jennifer Ahrens, who reported, Patients and carer responses noticeably referred to their fear and anxiety during a time of diagnosis of cancer and follow-up treatments. Most patients are grateful that the hospital provides this service, which they report as bringing diverse benefits, particularly on an emotional level and one that is personally supportive as they negotiate a stressful and traumatic period with less fear, anxiety or depression.

Reiki is not an alternative to allopathic medicine—it is a “complementary” therapy that can be implemented alongside all other medical and therapeutic techniques. It is a gentle technique that is suitable for even very fragile patients, so it is accepted widely in hospitals and hospices around the world. The profound relaxation produced by Reiki has been anecdotally reported to alleviate anxiety and stress, the perception of pain, and to promote a feeling of psychospiritual well-being.

Reiki was developed by Mikao Usui in Japan in the 1920s. It is a relaxing form of healing therapy that is applied through noninvasive, nonmanipulative gentle touch. Reiki involves lightly laying of hands just above or on the clothed body, working over the front and back in a slow progression of hand positions. Reiki has no religious doctrine and is accepted by people from all backgrounds and belief systems.

One of the key defining features of Reiki is that the ability to practice is conferred through an “attunement” process and is not dependent on any innate personal healing capability. Attunement is done by a Reiki master, through a series of rituals that are said to open the energy channels of the body. Attunement to first-degree Reiki (Reiki I) confers the ability to treat oneself and others by touch. Attunement to second-degree Reiki (Reiki II) confers the ability to use specific symbols to access Reiki mentally for distant healing. Attunement to third-degree Reiki (Reiki III), or master level, confers the ability to attune others into Reiki. At each level, the ability to effectively heal with Reiki develops progressively through committed practice.

Understandably, the ability to confer special healing abilities through an attunement ritual is regarded with skepticism by many people. It could be argued that any health benefits of Reiki are nothing more than a placebo effect and that the same benefits could be achieved without attunement. Reviews of Reiki clinical trials have been published by Lee et al, vanderVaart et al, and by Baldwin et al. In summary, these reviewers found that Reiki had some promise in the areas of pain, relaxation, and anxiety management, but there was a need for further experiments with greater numbers of subjects to allow statistically meaningful interpretation.

In recent years, there have been many new publications on Reiki trials, but these have not been subject to review. The present study was undertaken to review the available clinical studies of Reiki to determine whether there is evidence for Reiki providing more than just a placebo effect. Four selection criteria were applied to Reiki studies for inclusion in this review. First, only studies of hands-on Reiki were considered. While distance healing is considered to be a valid Reiki technique, there are currently too few published studies to draw statistical conclusions. Second, only quantitative studies including a “sham Reiki” placebo control were considered. Sham Reiki involves an actor mimicking the hand positions and other procedures used by the attuned Reiki practitioner. It is intended to serve as a placebo control, in which the only significant experimental variable is whether or not the practitioner has received a Reiki attunement. Third, this review only includes reports published in peer-reviewed journals, thereby excluding master’s and PhD theses. The rationale for this is that the methods and results in published articles have survived screening and evaluation by peer review, whereas master’s and PhD theses have not. Fourth, this review only includes studies involving 20 or more participants in the Reiki treatment arm. A criticism raised in previous reviews is that many studies were flawed by the use of too few experimental subjects, making them incapable of reaching statistically significant conclusions. The inclusion of studies with 20 or more participants helps ensure that the conclusions are statistically robust. The exception to this criterion is the inclusion of 2 studies that used laboratory rats as experimental recipients of Reiki. These were rigorously conducted studies that collected “hard” evidence through microscopic tissue examination and implanted telemetric transmitters, with care taken to ensure statistically significant outcomes. These are regarded as highly significant studies because they prelude the possibility of a psychological placebo effect. Even so, a sham Reiki placebo control was used in each study.

Identification of English-language Reiki studies was done by undertaking a Google Scholar search using a variety of key words, repeated over a period of more than 3 months. In addition, the reference lists of identified articles were also scrutinized, to help identify any additional references. Full copies of all identified publications were obtained, to ensure that experimental details were correctly understood. Only the publications meeting all of the selection criteria were included in this review. There were 13 peer-reviewed studies published between 1998 and 2016 that met all of the selection criteria. There were 4 randomized single-blind studies and 7 randomized double-blind studies with human participants, and 2 studies using rats. The studies included both pilot studies and clinical trials, looking at both short-term and long-term application of Reiki. To assist in the interpretation of these data, the selected studies can be grouped into 4 categories:

  1. Physiological responses to Reiki

  2. Use of Reiki as a complementary therapy for a chronic condition

  3. Use of Reiki as a treatment for a chronic condition

  4. Use of Reiki as a complementary therapy for an acute condition

Physiological Responses to Reiki Witte and Dundes conducted a randomized, placebo-controlled pilot study using university student volunteers to measure objectively the effect of Reiki on physical and mental relaxation. Reiki was provided by a Reiki I practitioner over a period of 20 minutes, involving 4 hand positions on head, neck, and upper torso of a seated participant. Four treatment arms were used, each with 25 participants: Reiki, sham Reiki placebo, a control group relaxing and listening to a meditation tape, and a control group listening to calming music. It was found that Reiki was more effective than placebo, music, or meditation for inducing physical relaxation, but there was no difference between groups for mental relaxation. Baldwin and Schwartz investigated whether application of Reiki could reduce the deleterious effects of noise-induced stress in rats. Loud noise can cause damage to the tiny blood vessels in the mesentery of rats, so the extent of microvascular damage can provide a quantitative measure of the level of stress experienced by the animals. The experiments involved 3 treatment arms: (1) noise + Reiki (n = 4), (2) noise + sham Reiki (n = 4), and (3) noise-only control (n = 4). Reiki or sham Reiki were provided to the caged rats for 15 minutes per day over 21 days. The experiment was replicated 3 times, and then again using different Reiki practitioners. It was found that the extent of stress-associated microvascular damage for noise + Reiki was significantly less than that for noise + sham Reiki or the noise-only control. Baldwin et al extended their earlier study to investigate whether Reiki can reduce the heart rate and blood pressure of noise-stressed rats. The rats were fitted with implantable telemetric transmitters to provide accurate physiological data. The same procedure was used as before, with 3 rats in each treatment arm and Reiki or sham Reiki provided for 15 minutes per day over 5 days. It was found that Reiki, but not sham Reiki, significantly reduced both the average resting heart rate and the rise in heart rate produced by exposure of rats to loud noise. However, neither Reiki nor sham Reiki significantly affected mean arterial pressure.

Díaz-Rodríguez et al employed a randomized, single-blind, placebo controlled, crossover design pilot study to investigate the physiological effects of Reiki in health care professionals with burnout syndrome. The study involved 21 participants receiving either Reiki or sham Reiki placebo, with heart rate variability, body temperature, salivary flow rate, and salivary cortisol levels measured both pre- and posttreatment. Reiki was provided by a practitioner with 15 years of experience, involving a 30-minute session covering the head, eyes, ears, and chest. It was found that a single session of Reiki increased heart rate variability and body temperature but not salivary cortisol levels, indicating that Reiki shifts the autonomic balance toward parasympathetic dominance. Salles et al investigated the effect of Reiki on abnormal blood pressure using a randomized, cross-sectional, descriptive, and double-blind clinical trial. Hypertensive patients were randomized to 1 of 3 treatment arms: (1) Reiki (n = 22), (2) sham Reiki placebo (n = 22), or (3) rest control (n = 22). Reiki was provided as a single 20-minute session (no details provided). It was observed that blood pressure decreased in each of the 3 groups, with statistically significant differences between each group. The Reiki group had the greatest reduction in blood pressure, followed by the placebo and the control group. All 5 of these studies provide evidence that Reiki is better than placebo for inducing a physically relaxed state. This appears to be an objective fact, given that it has been replicated in both humans and rats. Physiological measurements indicate that Reiki is more effective than placebo in reducing resting heart rate, increasing heart rate variability, and reducing blood pressure. These results indicate that Reiki is more effective than placebo in activating the parasympathetic nervous system.

Reiki as a Complementary Therapy for Chronic Conditions Dressen and