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fpsyg-13-897312 July 12, 2022 Time: 7:59 # 1
SYSTEMATIC REVIEW
published: 12 July 2022
doi: 10.3389/fpsyg.2022.897312
Edited by:
Helané Wahbeh,
Institute of Noetic Sciences,
United States
Reviewed by:
Garret Yount,
Institute of Noetic Sciences,
United States
Alice Branton,
Trivedi Global Inc., United States
*Correspondence:
Sonia Zadro
soniazadro@gmail.com;
sonia.zadro@student.bond.edu.au
Specialty section:
This article was submitted to
Psychology for Clinical Settings,
a section of the journal
Frontiers in Psychology
Received: 16 March 2022
Accepted: 20 May 2022
Published: 12 July 2022
Citation:
Zadro S and Stapleton P (2022)
Does Reiki Benefit Mental Health
Symptoms Above Placebo?
Front. Psychol. 13:897312.
doi: 10.3389/fpsyg.2022.897312
Does Reiki Benefit Mental Health
Symptoms Above Placebo?
Sonia Zadro*and Peta Stapleton
School of Psychology, Bond University, Gold Coast, QLD, Australia
Background: Reiki is an energy healing technique or biofield therapy in which an
attuned therapist places their hands on or near the client’s body and sends energy
to the client to activate the body’s ability to heal itself and restore balance. It was
developed in Japan at the end of the 19th century by Mikao Usui of Kyoto. Given
the enormous international socioeconomic burden of mental health, inexpensive, safe,
and evidenced-based treatments would be welcomed. Reiki is safe, inexpensive, and
preliminary research suggests it may assist in treating a wide variety of illnesses. Given
that Reiki is a biofield therapy, growing in use, and not yet accepted by the dominant
biomedical paradigm, it is important to establish its effectiveness over placebo. This
study aimed to examine Reiki’s effectiveness over placebo in treating symptoms of
mental health and to explore parameters for its effectiveness.
Method: A systematic review of randomized placebo-controlled trials (RPCTs)
examining Reiki’s effectiveness in treating symptoms of mental health in adults was
conducted through a systematic search of PubMed, PsycINFO, MEDLINE, CINAHL,
Web of Science, Scopus, Embase, and ProQuest. Fourteen studies met the inclusion
criteria, and risk of bias was assessed using Cochrane’s Revised ROB 2 assessment
tool. This was followed by a grading of recommendations, assessment, development
and evaluations (GRADE) assessment.
Results: The evidence to date suggests that Reiki consistently demonstrates a greater
therapeutic effect over placebo for some symptoms of mental health. The GRADE level
of evidence is high for clinically relevant levels of stress and depression, moderate to
high for clinically relevant levels of anxiety, low to moderate for normal levels of stress,
and low to moderate for burnout, and low for normal levels of depression and anxiety.
Conclusion: The results suggest that, Reiki may be more effective in treating some
areas of mental health, than placebo, particularly if symptoms are clinically relevant. To
date, there are a small number of studies in each area, therefore findings are inconclusive
and, more RCTs controlling for placebo in Reiki research are needed. Most included
studies were also assessed as having a risk of bias of some concern. Incorporating Reiki
as a complementary treatment to mainstream psychotherapy for depression, stress, and
anxiety may be appropriate.
Systematic Review Registration: [https://www.crd.york.ac.uk/], identifier
[CRD42020194311].
Keywords: Reiki, placebo, mental health, anxiety, depression, stress, burnout, systematic review
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Zadro and Stapleton Does Reiki Benefit Mental Health
INTRODUCTION
Complementary and alternative medicine (CAM) is a
heterogeneous group of practices that are not part of orthodox
medical care. They may include alternative medical systems
such as Chinese medicine, mind-body interventions such
as meditation, biologically based treatments such as herbs,
body-based approaches such as chiropractic care (NIH, 2005),
and biofield therapies which use the body’s energy field to
promote therapeutic benefit (Guarneri and King, 2015). Reiki is
considered a biofield therapy. It was developed in Japan at the
end of the 19th century by Mikao Usui of Kyoto (Baldwin, 2020).
It is a non-invasive treatment whereby the attuned practitioner
gently places their hands on or close to the body of a client in a
sequence of positions to promote the body’s ability to heal itself
and restore balance (Anderson and Wolk-Weiss, 2008).
Worldwide, one billion people suffer from a mental health
disorder (The Lancet Global, 2020), and mental illness accounts
for half of all illnesses for people up to 45 years of age in wealthy
countries (LayaRd, 2017). In 2010, mental health expenditure was
estimated to cost the world economy USD$2.5 trillion a year
because of poor health and reduced productivity, and this cost
is expected to increase to USD$6 trillion by 2030 (The Lancet
Global, 2020). Finding inexpensive, evidence-based, safe ways to
reduce this burden would be welcomed. Reiki is deemed safe,
inexpensive, and non-invasive and preliminary research suggests
that it may be effective in treating many illnesses, including
symptoms of mental health.
There is also evidence Reiki has therapeutic effects compared
with placebo on non-human living systems. Studies on Reiki’s
effects that best control for placebo are non-human studies
where we would expect placebo not to be operating or be less
influential. These include RPCT of Reiki’s influence on cell
cultures, isolated cells, rats and dogs. Despite this expectation in
all the following randomised controlled trials (RCTs), the placebo
effect was still controlled for with a placebo Reiki group, and all
produced significant therapeutic results (Baldwin and Schwartz,
2006;Baldwin et al., 2008;Mothersill et al., 2013;Kent et al.,
2020;Pacheco et al., 2021). In these five studies, Reiki was more
effective than placebo in the following areas: reducing noise-
induced microvascular damage in rats (Baldwin and Schwartz,
2006), improving heart rate homeostasis in rats (Baldwin et al.,
2008), increasing survival of directly irradiated cells (Mothersill
et al., 2013), increasing photon emission of intervertebral cells
in mice and increasing collagen 11 and aggrecan in mice
(Kent et al., 2020), and reducing postoperative pain in female
dogs undergoing elective minimally invasive ovariohysterectomy
(Pacheco et al., 2021). While the studies do not prove that Reiki
is beneficial over placebo in humans, they provide evidence that
Reiki can be beneficial over placebo in non-human living systems.
Complementary and alternative medicine (CAM) and Reiki
are also becoming frequently used and more accepted (Lepine,
2018), with reported rates of CAM use at 69% in Australia
(Xue et al., 2007), 76% in Singapore, 76% in Japan, and 75%
in South Korea (Wardle et al., 2018). According to the Center
for Reiki Research (Lepine, 2018), 60 hospitals and clinics offer
Reiki treatments in the United States (USA), and eight other
clinics offer it in other countries. Despite the growing use, it is
important to keep in mind that Reiki is a biofield therapy (B.T.)
belonging to the paradigm of biofield science, which has not
been fully established or accepted by the mainstream biomedical
paradigm. The biofield is believed to be an organizing energy
field of any living system that regulates and helps maintain the
biological system (Rubik et al., 2015). This notion is a shift from
the mechanical chemistry-based view of the current dominant
biomedical paradigm to an information-based view where the
biofield is a multi-level organizational concept where information
flows within and between various levels of an organism (Rubik
et al., 2015). Western biomedicine routinely examines electrical
fields from the heart, known as electrocardiograms (ECG), and
the brain, known as electroencephalograms (EEG). Biophysics
provides evidence that endogenous electromagnetic and other
energy fields influence tissue development, tissue repair, and
other processes. Energy medicine purports that sending low-level
signals to the body can help it heal, including energy healing
interventions and bio-electromagnetic device-based therapies
(Rubik et al., 2015). However, there are several sociological and
paradigmatic oppositions to biofield science as follows (Hufford
et al., 2015):
(1) Although research is emerging on causal factors to explain
the biofield, such as electromagnetic field properties of
electricity, magnetism, sound, and pH, they are not well-
understood (Kent et al., 2020) and therefore viewed as
unscientific (Hufford et al., 2015).
(2) Some scientists believe that biofield science is incongruent
and, therefore, a challenge to the current paradigm.
(3) Subtle energies are often viewed as central to biofield
healing. The notion that subtle energies exist is not
accepted by conventional science so they are often viewed
as psuedoscience.
(4) The idea of a biofield is often associated with a life
force or vitalism, that is, the historical notion of a force
behind consciousness. This was firmly rejected by modern
medicine and still is.
The above concerns point to a need for scientific inquiry
into whether Reiki is more effective then placebo, particularly in
the much needed area of mental health. This systematic review
aims to determine the level of evidence for Reiki’s effectiveness
over placebo and explore the parameters used when and if it
is more effective.
METHOD
Reiki’s effectiveness over placebo in treating mental health was
assessed by a systematic review (SR) of RCTs in which a placebo-
Reiki comparison group was included. In most randomized
placebo-controlled trials (RPCTs), of Reiki, an untrained Reiki
practitioner with no knowledge of Reiki is taught to mimic the
hand positions of the trained Reiki practitioner to control for
expectancy effects on participants. The participants are blind
to whether they are receiving real or sham Reiki. As much as
possible, all other conditions, room, lighting, time, sound, etc.,
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are kept the same as in the Reiki condition. To control for client
expectancy effects, creating a placebo-Reiki group goes beyond
standard RCT protocols and provides more rigorous evidence.
This study only focused on studies that compared hands-
on Reiki to a placebo Reiki group or controlled for placebo in
some other way. It did not include distant Reiki because it was
thought that the causal mechanisms operating might be different
for distant Reiki applications. Also, in the hands-on placebo Reiki
condition, while participants are not receiving Reiki, they often
receive touch unless Reiki is delivered close to but not touching
the body. Several studies suggest that the use of therapeutic touch
alone has benefits (Gagne and Toye, 1994;Hawranik et al., 2008;
So et al., 2008;Ana Cristina et al., 2016). As such, studies of
hands-on placebo Reiki involving touch may be examining the
benefits of Reiki over therapeutic touch and placebo.
Considerations in Studying Reiki
In examining whether Reiki has a therapeutic effect over placebo,
some considerations are as follows to achieve a therapeutic effect:
(1) How long and how many applications of Reiki are needed,
and is the dose varied for different conditions?
(2) What kinds of conditions does Reiki provide a therapeutic
effect for?
(3) If Reiki is therapeutic, how long do the benefits last?
(4) Do the length of time and number of applications vary
according to the level of training and experience of the
practitioner?
(5) If effective, do the benefits always occur during treatment,
or could they occur after treatment?
Inclusion Criteria for Review
While several reviews of randomized RCTs of Reiki’s effectiveness
have been conducted (Vitale, 2007;Lee et al., 2008;VanderVaart
et al., 2009;Joyce and Herbison, 2015;Zimpel et al., 2020;Morero
et al., 2021), only one focused solely on studies controlling for
placebo (McManus, 2017); however, it did not conform to the
systematic review (SR) methodology. The present study aimed
to provide an up-to-date review of RPCTs on the influence of
Reiki on mental health symptoms in adults that conformed to the
SR methodology and included an assessment of the risk of bias
(ROB) and the GRADE criteria. It also included a broader range
of inclusion criteria than McManus (2017) as follows:
P: Adults healthy or unhealthy 18 years or older, with or
without a formal diagnosis of a mental health condition.
I: Hands-on (touching or near the body) Reiki as a treatment
intervention regardless of frequency, duration, or level of
practitioner training.
C: A Placebo or Sham comparison group where Reiki
is mimicked and/or the receiver did not know whether
they received Reiki or not. Other comparison groups may
also be included.
O: Standardized, valid, and reliable outcome measures of
mental health symptoms and statistical analysis of results.
Published and unpublished studies were included, but only
those translated into English.
Despite other SRs of Reiki not meeting the inclusion criteria
of a placebo group, there are differences in other Reiki SRs’
worth noting. For instance, a Cochrane SR (Zimpel et al., 2020)
of “Complementary and alternative therapies for post-cesarean
pain” included a review of Reiki plus analgesia vs. analgesia.
This only included 2 RCTs (Midilli and Eser, 2015;Midilli and
Gunduzoglu, 2016), one of which did not have a placebo group
(Midilli and Eser, 2015). The limited number of studies may have
been due to four databases being searched rather than the eight
searched in this SR.
Another SR by Joyce and Herbison (2015) excluded studies
that were included in this SR because they did not meet the
criteria for being anxious or depressed (Dressen and Singg, 1998;
Shiflett et al., 2002;Mackay et al., 2004;Shore, 2004;Bowden et al.,
2010). These studies still used outcome measures of mental health
(met PICO), so they were included in this SR. Also, when baseline
pre-treatment mean scores were compared to accepted clinical
cutoffs, some studies that Joyce and Herbison (2015) excluded
were in the clinical range (Dressen and Singg, 1998;Shore, 2004),
and one study she included was in the clinical range for stress but
not anxiety and depression (Bowden et al., 2011). These clinical
discrepancies are highlighted in the results of this SR.
Research Questions
1. Does Reiki consistently demonstrate a therapeutic effect
above placebo for mental health symptoms?
2. If so, what variables appear to contribute to this therapeutic
effect, i.e., duration and frequency of treatment and level of
wellness?
Search Method
Randomized controlled placebo trials were researched on
PubMed, PsycINFO, MEDLINE, CINAHL, Web of Science,
Scopus, Embase, and ProQuest with the keywords ”Reiki,”
“sham,” “placebo,” “mock,” and “comparison treatment.”
Supplementary Appendix A lists the search terms used for
each database. Reference lists of identified studies were scanned
to search for additional studies. A total of 319 duplicates were
removed. One hundred and eighty-nine records were screened,
and of these, 150 were excluded and 39 were sought for retrieval.
Two reports were not retrieved and 37 were assessed for
eligibility. Two studies were in French, 4 used distant Reiki,
and 4, on closer inspection, had significant design flaws due
to non-randomization (Bessa et al., 2017), missing validated
post-test outcome measures (Mauro, 2001), no statistical tests
of significance (Salach, 2006), no validated outcome measures
(Bourque et al., 2012), and a focus on senders of Reiki rather
than recipients (Barnett, 2005). Finally, 12 studies with no
outcome measures of mental health were excluded and 14 studies
remained. The search was also conducted by an independent
assessor. The PRISMA flow chart detailing search findings can be
seen in Supplementary PRISMA Flow Diagram 1. The PRISMA
Checklist can be found in Supplementary Appendix B. The
PRISMA Abstract Checklist can be found in Supplementary
Appendix C.
The SR used the recently revised Cochrane Risk of Bias
Tool for randomized controlled trials (ROB 2). The suggested
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algorithms for judging risk of bias (ROB) were used as a guide
to help maintain objectivity (Sterne et al., 2019). The ROB 2 uses
a detailed template and an algorithm for judging ROB arising
from each of the following areas: randomization, assignment to
intervention, adhering to intervention, missing outcome data,
measurement in the outcome, and selection of the reported result.
ROB from period and carryover effects in crossover trials was
applied if applicable. All ROB 2s were independently reviewed,
and discrepancies were resolved. Full ROB 2 assessments for
each study are available at https://cloudstor.aarnet.edu.au/plus/
s/qI4RRkw4Ys8MFKr and effect size calculations at https://
cloudstor.aarnet.edu.au/plus/s/uCKeNLEjGLo5jId. A summary
of key information is presented in the results section Table
1(Summary of Main Findings). Extended information on
all studies is presented in Supplementary Table 1 (Extended
summary of findings) of the Supplementary Material. Effect
sizes were calculated for all RPCTs using an effect size calculator
(Wilson, 2017), and the results were randomly checked by
calculating Cohen’s d from t-tests (Thalheimer and Cook, 2002).
For four studies, effect sizes could not be calculated because of
insufficient published data (Shiflett et al., 2002;Rosada et al.,
2015;Erdogan and Cinar, 2016;Çinar et al., 2022).
Attempts were made to contact the authors of all the 14
studies to clarify unclear or missing information and provide a
fair review. Author contacts were searched for through Google,
LinkedIn, and Research Gate. No contact details were found
for the authors of one RPCT (Shiflett et al., 2002). Of the
remaining 13 RPCTs, the authors of four studies responded
(Thornton, 1991;Vasudev and Shastri, 2016;Baldwin et al., 2017;
Çinar et al., 2022).
RESULTS
The search found 26 randomized placebo controlled trials
(RPCTs) that examined hands-on Reiki’s effectiveness over
placebo in adults using valid outcome measures translated in
English (Thornton, 1991;Dressen and Singg, 1998;Witte and
Dundes, 2001;Shiflett et al., 2002;Mackay et al., 2004;Shore,
2004;Gillespie et al., 2007;Assefi et al., 2008;Bowden et al.,
2010, 2011;Catlin and Taylor-Ford, 2011;Díaz-Rodríguez et al.,
2011a,b;Ventura Carraca, 2012;Baldwin et al., 2013, 2017;Fortes
Salles et al., 2014;Novoa and Cain, 2014;Rosada et al., 2015;
Alarcao and Fonseca, 2016;Erdogan and Cinar, 2016;Midilli
and Gunduzoglu, 2016;Vasudev and Shastri, 2016;Bat, 2021;
Yüce and Ta¸scı, 2021;Çinar et al., 2022). Fourteen of these met
PICO for examining the effectiveness of Reiki over placebo in
measuring symptoms of mental health (Thornton, 1991;Dressen
and Singg, 1998;Shiflett et al., 2002;Shore, 2004;Bowden et al.,
2010, 2011;Díaz-Rodríguez et al., 2011a,b;Rosada et al., 2015;
Erdogan and Cinar, 2016;Vasudev and Shastri, 2016;Baldwin
et al., 2017;Yüce and Ta¸scı, 2021;Çinar et al., 2022). These RPCTs
included outcome measures of depression, anxiety, stress, and
burnout. No studies in this SR reported adverse effects of Reiki.
Anxiety and Stress
Eight peer-reviewed and one non-peer-reviewed RPCTs
using standardized outcome measures for anxiety and
stress met the criteria for inclusion. Six included measures
for anxiety (Thornton, 1991;Dressen and Singg, 1998;
Bowden et al., 2010, 2011;Baldwin et al., 2017;Çinar et al., 2022),
and five included measures for stress (Shore, 2004;Bowden et al.,
2010, 2011;Vasudev and Shastri, 2016;Yüce and Ta¸scı, 2021).
Thornton (1991) conducted an unpublished RPCT on the
effect of Reiki on adult healthy female nursing students
(Thornton, 1991). In this study, 42 healthy student nurses
were randomly assigned to either 1 h of Reiki (n= 22)
or 1 h of mock Reiki from a research assistant (n= 20).
The Spielberger State-Trait Anxiety Inventory was given pre-
post treatment. State and trait anxiety were lower in both
placebo and Reiki groups post-treatment; however, there were
no between-group differences between Reiki and sham groups
for state anxiety (p= 0.864) or trait anxiety (p= 0.35)
post-treatment. By direct contact with the author, participants
were randomized using a random numbers table. It is unclear
if the groups were equal at baseline as differences were
not statistically analyzed. All mean baseline scores (ranging
from 34 to 36) were under the cutoff of 39 for both
state and trait anxiety. These scores are considered clinically
insignificant (Julian, 2011) and likely decreased the impact
of Reiki in this study. The small sample size may have
also reduced power.
Contact with the author revealed that the assessors were not
blind and that Reiki was delivered by the author, a Reiki master
with 10 years of experience. Mainly the unblind assessors and
author delivery of Reiki leave this study with some concerns for
ROB. This study does not support the effectiveness of Reiki over
placebo in populations with anxiety in the normal range.
A larger study on adults who had been chronically ill for
at least 1 year with chronic pain was conducted by Dressen
and Singg (1998). One hundred and twenty participants were
randomly assigned to one of four groups: (1) Reiki, (2)
progressive muscle relaxation, (3) mock Reiki, and (4) the
control group that received no treatment but came to read
any material of their choice. Sessions lasted 30 min and were
conducted two times a week for 5 weeks. Forty-five percent of
the participants experienced pain from chronic headaches. Other
categories included pain from cancer, coronary heart disease,
arthritis, and hypertension. A sizeable significant reduction in
pain intensity global (p= 0.0001), depression (p= 0.0001), state
anxiety (p= 0.0001), and trait anxiety (p= 0.0001) was found in
the Reiki groups post-treatment, and it was stated that Reiki was
significantly more effective than placebo in all the areas (between-
group p-values not given). Large effect sizes were found for Reiki’s
effect over placebo for reducing state anxiety (d= 1.36), trait
anxiety (d= 1.07), and depression (d= 1.4). Also relevant to
mental health, Reiki was stated to be significantly more effective
than placebo in improving self-esteem, loss of control, and an
unrealistic sense of control as measured with validated outcome
measures (p-values not given). The subjects were partly self-
selected, and it was unstated whether the assessors were blind to
treatment assignment. No prespecified analysis plan was found,
and a 3-month follow-up was only assessed for the Reiki group.
Despite some concerns regarding ROB, this study supports the
effectiveness of Reiki in treating anxiety over placebo in those
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TABLE 1 | Summary of main findings.
Study Results
Between groups P-value and effect size d= 0.2
(Small) 0.5 (Medium) 0.8 (Large).
ROB 2 Critique
Clinical anxiety
GRADE: moderate to high
Çinar et al. (2022)
Fibromyalgia
Post 4th trt Reiki sig lower than placebo for state
anxiety (p= 0.005) and trait anxiety (p= 0.003).
Some concerns -No prespecified analysis plan was found.
-1 exclusion criteria may have introduced bias.
-Reiki was done by “an experimenter” but unclear
if it was an author.
Baldwin et al. (2017) Knee
Replacement Surgery
No between group comparisons made due to small
sample size of controls.
Within grp Reiki sig p= 0.004 and Placebo NS.
d(Reiki over placebo) = 0.93
Some concerns -If the Reiki size was better matched, placebo
Reiki may not have performed as well.
-Blinding was assessed as successful.
-No pre-specified analysis plan was found.
Dressen and Singg (1998)
Chronically ill and in pain.
Reiki sig >placebo (no p-value)
State Anx p= 0.0001 (pre/post) d= 1.36 >placebo.
Trait Anx p= 0.0001 (pre/post) d= 1.07 >placebo.
Some concerns -Unstated if assessors were blind.
-No pre-specified analysis plan was found.
-Follow-up Reiki scores were not compared to
other groups
Anxiety: normal range
GRADE: low
Bowden et al. (2011)
Mood and wellbeing in
High vs. Low Mood
HADS anxiety baselines not given Reiki not sig >Placebo.
DASS Anxiety (high mood) baseline borderline normal/low
(7)
Anxiety DASS High Mood p= 0.084 Low Mood p>0.05
Some concerns -Very small sample decreased power.
-Experimenter administered Reiki however well
blinded and participant blinding was assessed as
successful.
Bowden et al. (2010)
Well-being and salivary
cortisol in healthy psych
undergraduates.
Anxiety subscale DASS p= 0.295
d= 0.17 (L)
Some concerns -Author administered Reiki but unlikely influence
as sat behind a blindfolded SS with no touch
(blinding successful p<0.05)
-No pre-specified plan.
-Dropouts 14%
Thornton (1991)
Female Nurses
Unpublished
State Anxiety
p= 0.864 d=−0.16
Trait Anxiety p= 0.350 d=−0.12
Some concerns - Unnecessary as others small also.
-Assessors were not blind
-Baseline scores below the cut-off for clinical
anxiety and healthy population.
-Experimenter administered Reiki.
-Baseline differences not statistically analyzed.
Clinical stress
GRADE: high
Bowden et al. (2011)
Mood and wellbeing in
High vs. Low Anxiety and
Depression.
Sig
High Stress Reiki >placebo (p= 0.008). d= 0.87
d= 0.90 at f.up. Not sig in low mood (p<0.05) d
Some concerns -Baseline scores for wtress higher in Reiki group.
-Author administered Reiki but was unlikely to bias
outcome as sat behind blindfolded SS with no
touch (blinding successful p<0.05)
-No pre-specified plan.
Vasudev and Shastri
(2016)
Self-perceived
work-related stress
software professionals.
Hands on Reiki and DR Placebo p= 0.028 d= 0.63
No diff bet hands on Reiki and DR p= 0.878 suggests
benefits from hands on R not due to touch or other
placebo effects.
Some concerns -Hands on and distant Reiki was delivered by the
experimenter but instruction was given which
should have reduced placebo bias.
-Hands on Reiki > DR placebo and no difference
bet hands on Reiki and DR suggesting Reiki is not
influenced by the placebo factors.
-31% dropout rate (raw scores in thesis) though
reasons mostly random.
Yüce and Ta ¸scı (2021)
Stressed Caregivers of
cancer patients.
CSI p<0.001 at post-treatment 6 weeks. d= 2.3 Some concerns -Investigator administered Reiki and trained the
sham group.
-17% dropouts and no ITT analysis were reported.
Stress: normal range
Grade: low to moderate.
Bowden et al. (2010)
Well-being and salivary
cortisol in healthy psych
undergraduates.
NS (p= 0.054) stress subscale over placebo on DASS. Some concerns -Higher pre-stress scores in the Reiki group may
have assisted Reiki
-Author administered Reiki but was unlikely to
influence as sat behind a blindfolded SS with no
touch (blinding successful p<0.05)
-No pre-specified plan and 14% dropouts.
(Continued)
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TABLE 1 | (Continued)
Study Results
Between groups P-value and effect size d= 0.2
(Small) 0.5 (Medium) 0.8 (Large).
ROB 2 Critique
Shore (2004)
Depression and Self
Perceived Stress.
Perceived Stress Scale (PSS) post-test p= 0.029
d= 0.88
1 year follow up p= 0.001 d= 2.02
Some concerns -High drop out from post-treatment to f. up
through analysis of original numbers (73 to
46).
-Placebo R believed Hands On R was the
placebo to reduce expectancy.
- PSS-10 may not have captured stress
adequately.
Clinical depression
GRADE: high
Dressen and Singg
(1998)
Chronically ill and in
pain.
Reiki sig >placebo (no p-value)
P= 0.0001 pre-post. d= 1.4 >placebo
Some concerns -Unstated if assessors were blind.
-Subjects were self-selected in response
to an advertisement.
-No pre-specified analysis plan was found.
-Follow up Reiki scores were not
compared to other groups
Erdogan and Cinar
(2016)
Depression in the
Elderly.
Reiki sig >placebo at all 4 time measurements.
1st p= 0.001 4th p= 0.000
8th p= 0.000, 12th p= 0.000 (1 mthf.up). Inadequate
data to calculate d.
Some concerns -One of only 2 studies blinding sham
practitioners, i.e., Reiki done by the
researcher but Placebo Reiki practitioners
believed they were doing Reiki to control
for practitioner expectancy effects.
-NI whether outcome assessors were
blind.
Shore (2004)
Depression and Self
Perceived Stress.
Reiki >placebo Reiki p= 0.042 d= 0.74
1 yr follow up p= 0.001 d= 1.43
Some concerns -High drop out from post-treatment to f. up through
analysis on original numbers (73 to 46)
-Placebo R led to believe Hands On was the placebo grp to
reduce expectancy.
-SS self-selected in response to an advertisement as being
in need of treatment for self-perceived depression and
stress/anxiety.
Shiflett et al. (2002)
Functional Recovery
Post Stroke Rehab.
NS
Depression (p>0.05). Inadequate data to calculate
d-value.
HIGH -double-blinded, i.e., blinded practitioners
and participants.
-blinding practitioners were successful but
attunement may have not been successful.
-20 historic controls used.
-16% missing data and cognitive FIM
missing. ITT not done.
-No pre-specified analysis plan.
-Variation of 6–10 treatments/grp and
though not related to group assignment
may have still influenced outcomes.
Depression: normal range
GRADE: low
Bowden et al. (2010)
Well-being and salivary
cortisol in healthy psych
undergraduates.
NS (p>0.05 no values given). Some concerns -Author administered Reiki but was unlikely
to influence as sat behind a blindfolded SS
with no touch (blinding successful
p<0.05)
-No pre-specified plan.
-Dropouts 14%
Bowden et al. (2011)
Mood and wellbeing in
High vs. Low Anxiety
and Depression.
NS (p>0.05 no values given) Some concerns -Experimenter administered Reiki.
-Participant blinding was assessed as
successful.
-Baseline scores for stress were higher in
the Reiki group.
Burnout
GRADE: low to moderate
Díaz-Rodríguez et al.
(2011a) Nurses with
Burnout.
Reiki reduced diastolic BP >placebo p= 0.04 d= 0.59
and increased SIgA over placebo p= 0.04 d=−0.75
Systolic BP p= 0.24 a-amylase activity p= 0.71
Some concerns NI found on pre-register so maybe some
concerns are there.
Some research questions the use of
biological markers to measure burnout and
some supports it.
(Continued)
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TABLE 1 | (Continued)
Study Results
Between groups P-value and effect size d= 0.2
(Small) 0.5 (Medium) 0.8 (Large).
ROB 2 Critique
Díaz-Rodríguez et al.
(2011b) Health Care
Proff with Burnout. –
ECG recordings for SDNN Reiki >placebo (p<0.04),
d= 0.71
Body temp Reiki >Placebo (p= 0.02), d= 0.85
Salivary Cortisol p= 0.08, ECG RMSSD p= 0.06 HRV
non-sig.
Some concerns NI found on pre-register so maybe some concerns.
-blinding of participants was tested and found to be
successful.
- Greater significance across other measures may
have resulted from longer treatments and multiple
sessions as NS was borderline.
Some research questions the use of biological
markers to measure burnout and some supports it.
Rosada et al. (2015)
Burnout
Health care
professional.
Reiki >placebo Overall for burnout p= 0.011.
Reiki also reduced emotional exhaustion,
depersonalization, and increased pers
accomplishment (p<0.05 no values given).
Inadequate data to calculate d.
Some concerns -Unstated whether outcome assessors were blind.
-Published study excludes some non-significant
results from the original thesis.
-baseline numbers between groups for single
people were not given and this is important to some
results.
Bold indicates statistically significant results and moderate or larger effect sizes. NI means no information.
with chronic pain when the treatment is provided two times a
week for 5 weeks.
Bowden et al. (2010, 2011) conducted two studies that
included measures for anxiety, stress, and depression. In the
first study, Bowden et al. (2010) examined the effect of Reiki
and positive imagery on the wellbeing of and salivary cortisol
in 35 healthy psychology undergraduates with mental health
scores all in the normal range. The participants were randomly
assigned to one of the six groups, and all the groups were
asked to engage in a self-hypnosis/relaxation exercise. Three
groups (n= 18) underwent Reiki 3–30 inches above their head
with the experimenter seated behind them. The other three
groups were not administered Reiki but were told that they
were receiving Reiki (n= 17) while the experimenter sat behind
them with their hands at their side. Ten 20-min sessions were
given to both groups from between 2 and 12.5 weeks. All
the groups were blindfolded or wore headphones depending
on the task. Although the experimenter conducted Reiki in
the study, the additional steps to blind the subjects should
have reduced the influence of placebo. Blinding was tested
and found to be successful. Pre- and post-assessments were
conducted by a co-experimenter blind to the treatment groups.
In the first study, despite within-group improvements in anxiety
(p= 0.037) and stress (p= 0.001) but not in depression
(p= 0.102), there were no significant between-group differences
in the results for Reiki over placebo for anxiety (p= 0.295),
stress (p= 0.057), or depression (p= 0.152). Treatment delivery
ranged from 2 to 12.5 weeks; however, statistical analysis found
this to not to have an impact on outcomes. No prespecified
analysis plan was found, and “wellbeing” was operationalized
with the Depression, Anxiety and Stress Scale (DASS). This
is not a measure of wellbeing and likely not a sensitive
measure for participants all scoring in the normal range at
baseline. There was also a 14% dropout rate with no ITT
analysis. Overall, this study presents an ROB of some concern.
This study does not support the effectiveness of Reiki over
placebo for participants with mental health outcome scores in
the normal range.
In a replication of the above study (Bowden et al., 2011),
the same authors examined whether Reiki benefited mood
and wellbeing, but this time, they controlled for mood. Forty
university students, half with high anxiety and/or depression and
half with low anxiety and/or depression, were randomly assigned
to Reiki or placebo Reiki groups in the same arrangement as the
previous study. Despite being grouped separately according to
“high” and “low” levels of anxiety/depression, baseline scores for
the high mood groups still nearly all fell in the normal range on
the DASS. Depression baseline means were “normal,” and anxiety
means were borderline normal at a cutoff of 7 and “high” group
stress scores were in the clinical range (Lovibond and Lovibond,
1995). On the HADS, scores were in the mild to moderate range,
but no separate baseline scores were provided for anxiety and
depression, so this measure could not be assessed in this review.
Six 1/2 hour treatment sessions were administered between 2
and 8 weeks. Again, the impact of this variation was statistically
tested and found to not impact the outcomes. Blinding was
also tested and found to be successful. It is unstated whether
the assessors were blind, but it was expected given that it
is a replication of their previous study, which had blinded
assessors (Bowden et al., 2010) and the care taken to blind the
participants. There was no ITT analysis; however, there was a low
dropout rate of 7%.
Reiki reduced total DASS scores more than placebo for
the high mood group only, and although this did not reach
significance post-treatment (p= 0.075), it was significant at
follow-up (p= 0.045). Reiki significantly reduced stress compared
with placebo in the high mood group post-treatment (p= 0.008)
but did not reduce anxiety compared with placebo in high mood
(p= 0.084) or depression (no between-group means given). Effect
sizes for Reiki compared with placebo for stress were also large in
the high mood group post-treatment (d= 0.87) and at follow-up
(d= 0.9).
There was no prespecified analysis plan found for this study.
It is likely that the low sample size of ten per subgroup and low
baseline scores reduced the outcomes of significance. Overall,
this study presents an ROB of some concerns. These results
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provide support for Reiki’s influence over placebo at reducing
clinical levels of stress but not at reducing anxiety or depression
in the normal range.
Baldwin et al. (2017) examined the effects of Reiki on
pain, anxiety, and blood pressure in patients undergoing knee
replacement surgery. In this study, 46 adults scheduled for single
knee replacement surgery were randomly assigned to one of
three groups, all incorporating standard hospital care (Baldwin
et al., 2017): (1) three or four 30-min Reiki treatments by a
Reiki master, (2) three or four 30-min sham Reiki sessions with
an untrained person following the same hand positions as the
Reiki master from a printed protocol, and (3) three or four
sessions of quiet time. The participants and assessors were blind
to treatment assignment. Blinding was assessed and found to
be successful overall. The first session was 1 h prior to surgery,
and subsequent sessions 24, 48, and 72 h after the surgery if
not already discharged. Data were deidentified and collected by
trained data collectors. Anxiety was measured with the State-
Trait Anxiety Inventory, and the means met cutoffs for clinically
relevant anxiety at baseline (Julian, 2011).
Only the Reiki group showed significantly reduced state
anxiety scores as measured on the State-Trait Anxiety scale at
discharge (p= 0.004). The placebo group was non-significant;
however, the Reiki group could not be directly compared to the
placebo group, because the placebo group was too small for valid
statistical comparison because of dropouts. The magnitude of
effect for Reiki over placebo on anxiety was large (d= 0.93).
Despite no ITT analysis being performed, post-baseline dropouts
were controlled for by statistical analysis. Data from 48-h post-
surgery were treated separately by paired t-tests, which compared
pre-intervention and pre-surgery data, with patients discharged
48 h or more post-surgery.
If the Reiki sample size better matched that of the smaller
placebo group, Reiki may not have performed as well as it did. No
prespecified analysis plan was found. Overall, this study presents
an ROB of some concerns, and the outcomes suggest that Reiki
was more effective than placebo in reducing state anxiety in
populations with clinically relevant anxiety levels.
A recent study examined the effect of Reiki on stress levels
of caregivers of patients with cancer (Yüce and Ta¸scı, 2021).
In this study, 42 caregivers were randomly allocated to 45 min
of Reiki (n= 21) or sham Reiki (n= 21) once a week for
6 weeks. The caregivers met the cutoff scores for high stress on the
standardized Caregiver Strain Index (CSI). They and the assessors
were blind to treatment allocation. The investigator delivered
Reiki and trained four nursing students to identically deliver the
sham Reiki, increasing ROB. Though a strict application protocol
was followed. All baseline measures were similar between the
groups. Reiki performed significantly better than placebo with
high statistical significance on all measures except for salivary
cortisol. On week 6, the Reiki group had significantly lower
stress (CSI) scores than the sham Reiki group (p<0.001) with
a very large magnitude of effect (d= 2.3). A prespecified plan
was reported in clinicaltrials.gov. There was also a 17% dropout
rate with no evidence of an ITT analysis. Because of these
issues, this study had an ROB of some concerns. However, it
provides support for Reiki over placebo in treating high levels of
caregiver stress.
Another recent study evaluated the impact of Reiki on pain,
wellbeing, and anxiety in Turkish hospital patients treated for
pain from fibromyalgia (Çinar et al., 2022). Fifty patients were
randomly and blindly assigned to either 30 min of Reiki or sham
Reiki one time a week for 4 weeks, with 25 patients in each
group. The assessors were blind to the treatment group. Only
after the fourth treatment was Reiki found to reduce both state
anxiety (p= 0.005) and trait anxiety (p= 0.003) significantly
more than placebo. The data required to calculate effect sizes
could not be obtained from the author and therefore could not
be included. There were no baseline differences and no dropouts.
No prespecified analysis plan was found for this study. Overall,
it was assessed as having an ROB of some concerns but provided
evidence that Reiki can reduce state and trait anxiety compared
with placebo in patients who have fibromyalgia after four 30-
min sessions.
Self-Perceived Stress
Two peer-reviewed RPCTs have focused on the effects of Reiki
on self-perceived stress. Shore (2004) examined the long-term
effects of Reiki on depression and self-perceived stress. Forty-
six adults were randomly selected from a pool of respondents to
an advertisement for those seeking treatment for symptoms of
depression and stress. The participants were randomly assigned
to hands-on Reiki, distant Reiki, or distant Reiki placebo and
were blind to their treatment group. Reiki was performed
by an independent healer. The assessors were blind to group
assignment. All the groups (except placebo) were given 1 to 1.5 h
of Reiki one time a week for 6 weeks. Those in the distant Reiki
condition were in an identical room to those receiving hands-
on Reiki and were given the treatment from afar. Those in the
placebo distant Reiki condition were also in an identical room
and were told that they were given the treatment from afar but
were not given any treatment. The author states on page 43
that, “Participants in the hands-on Reiki condition believed they
were receiving mock Reiki and participants in the placebo distant
Reiki condition believed they were receiving distant Reiki (Shore,
2004).” This was conducted to reduce the effect of placebo further
but would have biased the outcome in favor of placebo in how
the groups were treated unequally. Despite this, the study still
produced results with high significance in favour of Reiki.
Baseline means were clinically relevant in the mild depression
range on the BDI. The means for the perceived stress scale were
very low at baseline and in the normal range. Post-treatment
showed a significant reduction in symptoms between the hands-
on Reiki and distant placebo Reiki treatment groups on the
Perceived Stress Scale (PSS) at post-test (p= 0.029) and at
1-year follow-up (p= 0.001). Effect sizes for perceived stress
were also large at post-treatment (d= 0.88) and very large at
follow-up (d= 1.43). There was also a significant reduction in
depression scores on the Beck Depression Inventory (BDI) at
post-treatment (p= 0.042) and at 1-year follow-up (p= 0.001),
with corresponding effect sizes of moderate at post-treatment
(d= 0.74) to very large at follow-up (d= 1.43). Significant
outcomes were also found for Reiki over placebo on the Beck
Hopelessness Scale (BHS) at post-treatment (p= 0.019) and
1-year follow-up (p= 0.009). Large effects of magnitude and
significance at follow-up should be treated with caution because
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of very high dropouts (40%) and no ITT analysis. However,
the reasons participants dropped out appeared to be random,
reducing bias from attrition. Initially, this study was published
as a dissertation.
This study shows an ROB of some concerns mainly because of
high follow-up attrition. It provides support for Reiki in reducing
normal levels of stress and mild clinical depression over placebo
in the short term and possibly with long-term effects.
Vasudev and Shastri (2016) studied 120 software professionals
suffering mainly from work-related stress and working at a firm
in Bangalore, India. The participants were randomly assigned
to hands-on Reiki, distant Reiki, distant placebo Reiki, or no
Reiki (control). Reiki was applied in the treatment groups
5 min per day for 21 days. The placebo participants were told
that they would receive Reiki, but they did not, to control
for expectancy effects, again biasing the outcomes in favor of
placebo. All the four groups were assessed pre- and post-21 days
of treatment with the 14-item Perceived Stress Scale. Direct
contact with the author confirmed that the assessor was blind to
group assignment. In the original thesis, additional scales were
also used as follows: Coping Checklist (Rao et al.) and WHO
(Five) wellbeing index, sociodemographic checklist, and stressor
inventory (Vasudev and Shastri, 2016).
In this study, a significant difference between groups occurred
for perceived stress, but it did not specify which of the
three groups were compared. However, the original thesis
identified that a significant difference between hands-on Reiki
and distant placebo Reiki (p= 0.028) was found. This had
a medium magnitude of effect (d= 0.63). The experimenter
administering Reiki used hands-on elements such as touch and
body language which could have increased the ROB favoring
the hands-on Reiki treatment condition. However, there was no
statistical difference between the hands-on Reiki and distant Reiki
treatment conditions (p= 0.878), and distant Reiki was also more
effective than placebo distant Reiki (p= 0.019). This suggests that
placebo factors of experimenter bias and the hands-on placebo
elements of touch and body language were not significant.
The thesis identified several other omissions from the
published article that favored both experimental and placebo
outcomes and were therefore unlikely due to bias. Direct feedback
from the author supports this: “The publisher said I had too much
content, so I had to cut it short.” There was a high dropout rate
of 31%. No ITT analysis was confirmed by direct contact with
the author. The author stated the main reason for attrition was
being unable to maintain regular attendance at the sessions, so
it is unclear if this was random. Although Reiki was given with
high frequency (21 days), it was only given for 5 min at a time.
A greater effect may have been found with a longer treatment
period. This study showed an ROB of some concerns mainly
because of high attrition rates and no ITT analysis but supports
the use of Reiki over placebo for normal levels of stress.
Conclusion on the Effects of Reiki on
Anxiety
All of the above six studies measuring the effects of Reiki
on anxiety showed an ROB of some concern, but none had
methodological issues too great to suggest that the outcomes
were significantly compromised. Of the three RPCTs measuring
clinically relevant anxiety, two had significantly reduced anxiety
in the Reiki group compared with placebo (Dressen and Singg,
1998;Çinar et al., 2022). The other (Baldwin et al., 2017) did
not directly compare the Reiki and placebo groups, but only
the Reiki group had significantly reduced anxiety. Where effects
could be calculated in two studies, large to very large magnitudes
of effect for Reiki over placebo were found for treating anxiety.
This provides support that Reiki can reduce anxiety compared
with placebo in people with clinically relevant levels of anxiety.
The three RPCTs that did not meet clinical cutoffs for anxiety
produced non-significant results directly comparing placebo and
Reiki for anxiety (Thornton, 1991;Bowden et al., 2010, 2011).
This suggests that Reiki is not more effective than placebo in
reducing anxiety in the normal range.
Conclusion on Reiki’s Impact on Stress
None of the above five studies measuring the effects of Reiki on
stress showed a ROB, which would suggest that the outcomes
were seriously compromised, that is, all ROBs were of some
concern (Shore, 2004;Bowden et al., 2010, 2011;Vasudev and
Shastri, 2016;Yüce and Ta¸scı, 2021). For clinically relevant
outcomes, Reiki was found to be highly significant compared
with placebo, and with medium to very large effect sizes in three
studies (Bowden et al., 2011;Vasudev and Shastri, 2016;Yüce and
Ta¸scı, 2021). Reiki was also suggested to be effective with those
experiencing normal levels of stress. Reiki showed significant
effects over placebo, with a large magnitude of effect on reducing
stress in Shore (2004) et al.’s (2010) study. These results suggest
that, compared with placebo, Reiki assists in reducing clinically
relevant stress and may reduce normal levels of stress.
Depressed Mood
There have been six RCPTs in which Reiki has been compared to
placebo with reducing scores on validated outcome measures of
depression (Dressen and Singg, 1998;Shiflett et al., 2002;Shore,
2004;Bowden et al., 2010, 2011;Erdogan and Cinar, 2016).
Reiki significantly reduced the symptoms of depression in
chronically ill patients (Dressen and Singg, 1998). This study has
previously been reviewed in the section on anxiety. The study’s
largest significant treatment effect was found for Reiki on treating
depression as measured by the Beck Depression Inventory 11
(p= 0.0001 post-treatment). Reiki was also significantly more
effective than placebo (no between group p-value was provided),
and the magnitude of the effect was large (d= 1.4). Depression
baseline means were all clinically relevant and in the mild range
for women and moderate range for men. This study was assessed
as having an ROB of some concerns and supports the hypothesis
that Reiki reduces clinical levels of depression compared with
placebo in the short-term.
A study on functional recovery for patients undergoing post-
stroke rehabilitation (Shiflett et al., 2002) included outcome
measures for the effect of Reiki on depression. Here, 30 patients
were randomly allocated to Reiki by a Reiki master (n= 10), a
Reiki novice (n= 10), or a sham Reiki (n= 10). An additional
twenty historic control patients were used. Six to ten 30-min
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sessions were given over 2.5 weeks for each of the Reiki, Reiki
novice, and sham Reiki conditions. This was double-blinded
in that the Reiki novice and sham Reiki practitioners did
not know whether they had been attuned with Reiki. Various
analyses suggest that this was likely successful. The outcome
measure for depression was The Centre for Epidemiological
Studies Depression Scale (CES-D). The CES-D baseline cutoff
means for clinical levels of depression were low but mostly met.
This study did not support the use of Reiki for clinical levels
of depression. However, there were significant methodological
problems. The baseline scores revealed statistically significant
differences between age and severity of impairment. These were
used as covariates to correct for this difference, but this still
may have influenced outcomes. The method of Reiki attunement
was questionable, as it appeared to have been conducted at a
distance (not hands-on) with all the practitioners together in the
same room. The arrangement for blinding the Reiki practitioners
meant that the novice practitioners used in the study had no
experience with a basic level of training having been attuned to
level 1. Reiki is believed to flow more strongly with higher levels
of attunement and more years of experience, so this is not ideal.
There were an uneven number of treatments of 6 to 10 for each
condition, although it stated that this was unrelated to group
assignment, functional status, mood, or FIM score. The dropout
rates were at least 16%, and no ITT analysis was conducted. It
is not stated whether the outcome assessors were blind, although
we might expect so given that the therapists and participants were
blind. The cognitive portion of the FIM was missing, which likely
influenced the outcomes for functional recovery and raised issues
regarding general data storage. There was also no prespecified
analysis plan. Overall, this study’s ROB was assessed as high, and
the results should be treated with caution. Also, effect sizes could
not be calculated because of insufficient data.
Shore (2004) examined the long-term effects of Reiki on
depression and self-perceived stress in volunteers. This study was
reviewed in the section on stress. BDI scores were above the
cutoff for being mildly clinically depressed. Reiki resulted in a
significant reduction in depression compared with placebo on the
Beck Depression Inventory (p= 0.042) and maintained this at
1-year follow up (p= 0.001), along with medium effects at post-
treatment (d= 0.74) to very large effects at follow-up (d= 1.43).
The ROB for this study was assessed as having some concerns,
but it provided evidence that Reiki reduces depression compared
with placebo in the short term and possibly in the long term in
people who are mildly clinically depressed.
Two RPCTs by Bowden et al. (2010, 2011), where the subjects
exhibited normal baseline scores for depression, showed no
evidence that Reiki had a therapeutic effect when compared with
placebo Reiki (Bowden et al., 2010, 2011). These studies have been
reviewed in the sections on anxiety and stress, and both were
assessed as having an ROB of some concerns.
In another RPCT, 90 elderly depressed volunteers living in
a nursing home in Istanbul (Erdogan and Cinar, 2016) were
randomly and blindly allocated to 45- to 60-min sessions one
time a week for 8 weeks. The sessions were Reiki, sham Reiki,
or a waitlist control. The therapist was “a researcher who
(was) a Reiki master (p37),” and it was unclear if this was the
author of the study. The sham Reiki group was applied by
four nurses who did not have training in Reiki but believed
that they were practicing Reiki. This should have helped to
control for differences in expectancy effects between the Reiki
and placebo Reiki practitioners. In this way, this study controlled
for both participant and practitioner biases. There appear to
be no dropouts in this study. Reiki was applied in the same
room and at the same time as real Reiki. The outcomes were
measured with the Geriatric Depression Scale (GDS) after the
1st, 4th, 8th, and 12th weeks (i.e., at 1-month follow-up), and
Reiki was found to be significantly more effective at reducing
depression than both placebo Reiki and the control across
all four-time measurements over the 12 weeks with highly
statistically significant outcomes at every measure (p= 0.001
post week 1 and p= 0 thereafter). Effect sizes could not be
calculated because of insufficient data. All the participants scored
at least 14 on the GDS at baseline, falling at least in the
moderately clinically depressed range (Laudisio et al., 2018).
It is not clear how the 45- to 60-min treatment time was
distributed between conditions, but this was unlikely to account
for such high levels of difference between groups. It is also not
stated whether the researcher, who was the outcome assessor,
was blind to the treatment assignment. Overall, this study was
assessed as having some concerns but provides evidence that
Reiki is more effective than placebo in reducing depression
in the short term and the long term in moderately depressed
elderly populations.
Conclusion on Reiki’s Impact on
Depression
Of the six Reiki RPCTs measuring depression, only one RPCT
had significant methodological issues that may have resulted in
invalid outcomes (Shiflett et al., 2002). The remaining five studies
all showed an ROB of some concerns. For the two RPCTs in
which baseline scores for depression were in the normal range,
Reiki had no effects of significance over placebo (Bowden et al.,
2010, 2011). In the other three RPCT where baseline scores
were clinically relevant, all found that Reiki was more effective
than placebo at reducing depression (Dressen and Singg, 1998;
Shore, 2004;Erdogan and Cinar, 2016), and where calculations
were possible, in studies with clinically relevant baselines, all
showed large to very large effect sizes. This provides support
that Reiki is effective in reducing clinically relevant symptoms of
depression compared with placebo but does not support Reiki’s
ability to reduce depression in the normal range.
Burnout
Three RCPTs have examined the effects of Reiki on burnout over
placebo (Díaz-Rodríguez et al., 2011a,b;Rosada et al., 2015), two
of which used biomarkers to measure burnout (Díaz-Rodríguez
et al., 2011a,b). In these studies, the author cited literature which
states that the stress response stimulates the sympathetic nervous
system and blood pressure and that several biological markers
are often used to measure stress. While some literature supports
the relationship between stress and blood pressure (Gasperin
et al., 2009;Ayada et al., 2015) and the relationship between
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biomarkers and burnout (Deneva et al., 2019;Bayes et al., 2021),
some research does not (Danhof-Pont et al., 2011).
Díaz-Rodríguez et al. (2011a) examined whether Reiki given
to nurses with burnout syndrome had beneficial effects on
biomarkers for burnout and stress. The biomarkers measured
were concentrations of salivary IgA, α-amylase activity, and
blood pressure. Eighteen adult nurses diagnosed with burnout
syndrome by a psychologist using the Maslach Burnout inventory
Manual were randomly assigned to 30 min of Reiki or sham Reiki.
The participants and data collectors were blind. Blood pressure
was measured with an Omron HEM-737 validated device, with
measurements performed in triplicate and the average taken for
analysis. There were no dropouts. The Reiki group produced
a significant decrease in diastolic blood pressure compared to
placebo (p= 0.04) with a medium magnitude of effect (d= 0.59).
Reiki also showed a significant increase in SigA concentration
compared to placebo (p= 0.04) with a medium magnitude of
effect (d= –0.75). The magnitude is negative because of an
increase in SigA, which suggests an improvement in immune
function. Compared with placebo, Reiki had no significant effect
on systolic blood pressure (p= 0.24) or a-amylase activity
(p= 0.71). It was concluded that a single 30-min session of Reiki
led to immediate improvement in the innate immune function
(SigA) and blood pressure regulation, which the placebo effect
could not explain. A prespecified analysis plan was not found.
This study was assessed to have some concerns. It provides
support for Reiki in treating biomarkers of burnout.
In a similar study (Díaz-Rodríguez et al., 2011b), 21 healthcare
professionals diagnosed with burnout by a psychologist using
criteria from the Maslach Burnout Inventory Manual were
randomly assigned to 30 min of Reiki or sham Reiki. Again,
biomarkers of burnout and stress were measured using validated
instruments and standardized procedures. The biomarkers
measured were heart rate variability (HRV), cortisol from salivary
flow rate, and body temperature (which used the OMRON
Gentle Temp 510). The participants were randomly assigned, and
the participants and data collectors were blind. There were no
dropouts. Only 19% of the participants identified their treatment
group correctly, so blinding was successful. All the sessions
occurred in the morning between 9 am and 12 pm, and the
subjects abstained from food, alcohol, caffeine, and exercise 2 h
prior to assessments. Interventions were given after 20 min of
rest. ECG recordings for SDNN were significantly higher than
placebo (p<0.04.) with a moderate effect (d= 0.71). Body
temperature was significantly higher than placebo after Reiki
(p= 0.02) with a large magnitude of effect (d= 0.85). The
authors stated that the higher body temperature was significantly
correlated with the LF domain after Reiki (p= 0.02), suggesting a
therapeutic effect on the parasympathetic nervous system. When
compared with placebo, Reiki had no significant effect on salivary
cortisol (p= 0.08) and ECG RMSSD (p= 0.06). The authors
concluded that Reiki positively influenced the parasympathetic
nervous system when applied to the healthcare professionals
with burnout syndrome. Once again, a prespecified analysis
plan was not found. This study was assessed to having an ROB
of some concerns. It supports the use of Reiki for treating
biomarkers of burnout.
Reiki was also found to reduce burnout among community
mental health clinicians (Rosada et al., 2015). Forty-five mental
health clinicians were randomly and blindly allocated to 30 min
of Reiki one time a week for 6 weeks or 30 min of sham
Reiki one time a week for 6 weeks in a randomized controlled
crossover design. Burnout was measured with the Maslach
Burnout Inventory. The participants were self-selected volunteers
working at mental health agencies. There was no information on
whether the assessors were blind to the treatment assignment,
and the dropout rate was 4%. Reiki was more effective than
placebo Reiki overall in decreasing burnout (p= 0.011). When
compared with placebo, Reiki also significantly reduced burnout,
as evidenced by decreased emotional exhaustion, decreased
depersonalization, and increased personal accomplishment on
the scale (p-values not provided). Effect sizes could not be
calculated because of insufficient data. The 6-week washout
period in this crossover design appears to have prevented a
carryover effect because when the Reiki treatment was provided
in the first 6 weeks, it was more effective than when it was
provided in the second 6 weeks. The original more detailed thesis
describes two additional assessments: the Social Readjustment
Rating Scale (SRRS) and the Perceived Self Efficacy Scale.
These both produced insignificant results. Furthermore, although
overall Reiki was significantly more effective than sham Reiki on
the Maslach Burnout Inventory (MBI) (p= 0.011), it was only
significant on the individual scales of the MBI and on the primary
symptom of the MYMOP for single people (pnot provided).
While being single may be relevant to burnout, the proportion of
single people was not reported in baseline characteristics, which
are important to these outcomes. This selective reporting and the
absence of information about the blinding of assessors leave this
study with an ROB of some concerns.
Conclusion on Reiki’s Impact on Burnout
Of the three RPCTs conducted on the influence of Reiki over
placebo to reduce burnout, none had significant methodological
issues, which would suggest the outcomes to be invalid. All
the three RPCTs found significant effects for Reiki over placebo
in treating burnout in healthcare professionals with mostly
moderate effect sizes for those that could be calculated. The three
studies provide evidence that Reiki reduces burnout over placebo
in healthcare professionals in the short term.
GRADE RANKING
In accordance with GRADE guidelines, a GRADE ranking was
applied to each mental health area under study (Brozek et al.,
2021;Schünemann, 2022;Siemieniuk, 2022). It is often reported
that Reiki energy flows according to the degree of imbalance a
person is experiencing and when it is needed (Webster, 2016;
Powers, 2018;Frazier, 2020) and stops flowing when the balance
is restored. Given this, it was expected that the more clinically
unwell the population under study, the more therapeutic impact
the Reiki would have. A number of studies in this SR used healthy
populations with mental health scores in the normal range, in
other words, scores that were clinically irrelevant. It was expected
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that Reiki would have a minimal effect over placebo in these
populations, just as one might expect almost any treatment to
produce a limited effect on a healthy normal individual with
nothing to treat. This appeared to be the case. Most studies did
not screen for a diagnosis of mental health, particularly, as many
used healthy participants.
To encourage consistency in the populations of studies under
review, standardized mental health outcome measurements were
grouped into populations with baseline means reaching cutoffs
for clinical levels of mental health (low range or higher) and
studies with baseline means falling in the normal range. Burnout
was not grouped this way because, in two studies, the population
met a diagnosis of burnout, and in the other study, it was not
assessed. In this study, health professionals were self-selected for
burnout, and it was not stated whether cutoff scores for burnout
were met (Rosada et al., 2015). Means were also not provided.
GRADE is assessed according to the following criteria: ROB,
inconsistency, indirectness, imprecision, and publication bias.
The studies are then checked for factors that may upgrade
the GRADE assessment (Schünemann, 2022;Siemieniuk, 2022).
According to GRADE guidelines an RCT, and more so one
that controls for placebo, begins at a GRADE ranking of
High. In the ROB criteria, only one study showed high ROB
(Shiflett et al., 2002), and this showed non-significant results
for those with clinically relevant scores of low depression.
All the other studies showed an ROB of some concerns, but
none had methodological issues serious enough to suggest
that the results were invalid. It is important to note that an
ROB of some concerns does not necessarily affect GRADE
outcomes, as the ranking is not a result of averaging the ROB
across studies but carefully considering the contribution of each
study, and they recommend this to be done conservatively
(Schünemann et al., 2013). “One should be conservative in the
judgment of rating down. That is, one should be confident
that there is substantial risk of bias across most of the body
of available evidence before one rates down for risk of bias
(5.2.1).”
With respect to the criteria of inconsistency, this was assessed
as follows: populations were drawn from university hospitals (4
studies), undergraduate students (3 studies), self-selected or GP
referred (3), one acute care hospital, one community mental
health agency, one rehabilitation institute, and one nursing home.
Six studies were conducted in the United States, three in Turkey,
two in the United Kingdom, two in Spain, and one in India. One
study used 58% men, three gave no percentages, another three
used 100% women, and the remainder used over 50% women.
Despite this variation in settings, country, and gender,
no studies used populations hospitalized for a mental health
condition. All the studies only used Reiki as the treatment under
study although in varying dosages and with practitioners who had
varying levels of training and experience. A number of studies
applied Reiki to populations that were healthy or unhealthy
but with normal (clinically irrelevant) levels of anxiety, stress,
or depression. As mentioned, this was thought to influence
outcomes, so studies were grouped according to normal vs.
clinically relevant scores. In this way, consistency was improved,
and all showed expected trends. On the whole, despite some
variations, it was determined that there was enough consistency
not to decrease the level of GRADE ranking.
All the studies met the criteria for indirectness; that is, all
clearly met PICO inclusion criteria and measured what they
were meant to measure. For the criteria of imprecision, the small
sample sizes across most of the studies would have increased
imprecision, decreasing the GRADE down by one level to a
grade of Moderate. For publication bias, while the small sample
sizes across most of the studies would have increased publication
bias, the systematic search across multiple databases would have
eliminated or reduced this bias, so the GRADE assessment was
not decreased. This leaves all areas at a GRADE level of moderate
because of the criteria of imprecision. However, GRADE can also
increase one level when there are large effects or when there
are dose-response relationships (Schünemann, 2022;Siemieniuk,
2022), and this will now be assessed.
Anxiety GRADE
The three RPCTs with populations meeting clinical cutoffs for
anxiety produced SOME highly significant results for Reiki’s
effectiveness over placebo (p= 0.003, p= 0.004, and p<0.05),
or as has been noted by Baldwin et al. (2017) for Reiki post-
treatment (p= 0.0001) and not placebo post-treatment. Where
they could be calculated, the effect sizes for Reiki, compared with
placebo, in two studies ranged from large to very large (d= 0.93,
1.36, and 1.07). However, because Baldwin et al. (2017) treatment
and placebo groups were not directly compared, GRADE was
only increased to a level of moderate to high.
The three studies with normal anxiety scores all produced
non-significant results for Reiki’s influence compared with
placebo. Here, compared with placebo, the overall GRADE
ranking for Reiki in reducing normal anxiety was low.
Stress GRADE
In the three RPCTs using populations with clinically relevant
stress scores, the findings were all highly significant for Reiki
compared with placebo (p= 0.028, 0.008, and 0.001). They also
all produced large or very large effect sizes (d= 0.97, 0.9, and
2.3) except for Vasudev and Shastri (2016), which produced a
moderate effect (d= 0.63). Overall, compared with placebo, this
would increase the GRADE to a level of high for Reiki’s influence
on reducing clinically relevant levels of stress.
For the two RPCTs on stress with outcomes in the normal
range, one (Shore, 2004) found significant results for Reiki over
placebo post-treatment (p= 0.029) and at 1-year follow-up
(p= 0.001). As previously noted, this follow-up score should be
treated with caution because of high dropouts. Shore’s (2004)
study also found large effect sizes post-treatment (d= 0.88)
and very large effect sizes at follow-up (d= 2.02). While the
participants did not meet the cutoffs for clinical stress in this
study, they met the cutoffs for depression and reported being
anxious and stressed. It may be that the PSS-10 did not capture
their stress levels adequately or that Reiki, compared with
placebo, is also effective at reducing normal levels of stress.
These outcomes suggest a low to moderate level of evidence
that Reiki is more effective than placebo in reducing stress in
the normal range.
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Depression GRADE
For the area of depression, in three of four studies using clinically
relevant scores, all produced statistically significant results for
Reiki over placebo. The RPCT that did not produce significant
outcomes had a high ROB, and as such, the outcomes were
likely compromised. For the other three RPCTs with significant
outcomes, effect sizes could be calculated in two studies (Dressen
and Singg, 1998;Shore, 2004), and both showed some very large
(d= 1.43 and 1.4) as well as moderate effects (d= 0.74). The
other study (Erdogan and Cinar, 2016) provided insufficient
data for the effects to be calculated but showed very high levels
of significance across all the time points including follow-up
(p= 0.001 to p= 0). Because of the large effects and consistent
significant findings for Reiki, the GRADE level was increased by
one. It was concluded that, compared with placebo, there was
a high level of evidence for the influence of Reiki on reducing
clinically relevant levels of depression.
The two other depression studies with clinically irrelevant
scores produced no significant effects for Reiki when compared
with placebo. As such, the GRADE assessment for Reiki reducing
normal-range depression when compared with placebo is low.
Burnout GRADE
Reiki showed significant results when compared with placebo for
all the burnout studies. However, they were not highly significant,
which may have been because two studies were based on only a
single 30-min session of Reiki (Díaz-Rodríguez et al., 2011a,b).
It would be interesting to see if the significance increased with
a more extended session of Reiki and/or multiple applications
and whether the effects of Reiki lasted at follow-up, which were
not assessed. There were insufficient data to calculate effect sizes
for Rosada et al. (2015) study, and the effect sizes for Díaz-
Rodríguez et al. (2011a,b) two studies were mostly moderate
(d= 0.59, 0.75, and 0.71) to large (d= 0.85). These effect sizes
were not sufficient to increase the GRADE ranking. Also, as
noted earlier, there is some contention as to whether biomarkers
adequately operationalize burnout. For this reason, the level of
evidence for burnout was downgraded overall to low to moderate.
A summary of findings for the reviewed RPCTs along with levels
of significance, effect sizes, and ROB 2 and GRADE assessments
are presented in Table 1.
DISCUSSION
To answer to the first research question, to date, the evidence
suggests that, compared with placebo, Reiki consistently
demonstrates a therapeutic effect on some symptoms of mental
health. When Reiki is applied to people with clinically relevant
levels of mental health, the GRADE level of evidence is moderate
to high for anxiety and high for stress and depression in reducing
symptoms over placebo. For people with stress levels in the
normal range, the GRADE level of evidence was low to moderate
in reducing stress when compared with placebo. When Reiki
was applied to people with anxiety and depression in the normal
range, the GRADE level of evidence was low for reducing anxiety
or depression when compared with over placebo. When Reiki was
applied to people with burnout, the GRADE level of evidence was
low to moderate in reducing burnout.
Overall, the number of studies in each area is small, and
further research is required to confirm the conclusions. A detailed
discussion on how well the placebo effect was controlled for by
the studies in this review will now be explored. This is followed
by a discussion on the second research question; what parameters
other than the level of wellness might influence the effectiveness
of Reiki over placebo?
Controlling for Placebo
The placebo effect is powerful and has the ability to alter our
biology and enhance our mood (Hamilton, 2021). According
to Benson and Friedman (1996), three factors contribute to the
placebo effect:
Criterion 1. Placebo can increase positive expectations of the
client and influence their beliefs and/or biology to produce the
real effect under study (Benson and Friedman, 1996;Hamilton,
2021).
Criterion 2. Placebo can affect the expectations of the
practitioner, which in turn influences the expectations
of the client to produce the real effect under study
(Benson and Friedman, 1996).
Criterion 3. The strength of the relationship between the
practitioner and the client can influence client expectations
in such a way as to produce the effect under study
(Benson and Friedman, 1996).
How well each of these factors was controlled in the studies
under review will now be discussed.
Criterion 1: Participant expectations.
All RPCTs in this systematic review met Criterion 1, in that
they controlled for participants’ expectations. In three RPCTs, the
blinding of participants was also tested and found to be successful
(Bowden et al., 2010, 2011;Baldwin et al., 2017).
Criterion 2: Therapist expectations.
Two RPCTs additionally controlled for therapist expectations
(Shiflett et al., 2002;Erdogan and Cinar, 2016). To achieve this,
the practitioner must believe that they are administering the
treatment of choice but really provide a treatment that cannot
produce an effect. In Erdogan and Cinar’s (2016) study on elderly
depressed patients, the sham practitioners were four nurses who
did not have training in Reiki but were made to believe they were
practicing Reiki. Details about how the blinding was achieved
were not provided. The study produced highly significant long-
term effects of Reiki when compared with placebo on treating
depression in the elderly. Shiflett et al.’s (2002) study on the effect
of Reiki when compared with placebo on functional recovery and
depression in stroke victims also blinded a group of sham Reiki
practitioners and found no significant effects of Reiki compared
with placebo. They blinded the novice practitioners by telling
them that they may or may not be attuned to Reiki and then only
attuned half of the group of novice practitioners while pretending
to attune the other half. This blinding was assessed as successful,
but the success of attunement was questionable because it was
done at a distance. As discussed, the study had other significant
methodological issues resulting in high ROB.
Criterion 3: Strength of the relationship.
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The strength and quality of the relationship can also influence
outcomes, and this is commonly reported to be an important
therapeutic influence in psychotherapy sessions (Flückiger et al.,
2018). In the Reiki sessions under study, several factors would
have reduced this kind of placebo influence. In all the RPCTs, the
therapists and the clients were not allowed to speak or speaking
was kept to a minimum. Therefore, verbal cues would have been
minimal or non-existent. In some of the RPCTs, sensory cues
were further minimized. In Bowden et al.’s (2010,2011) studies,
there were no sensory cues, i.e., the client was blindfolded while
the therapist stood behind them and did not touch them or speak.
Both studies by Díaz-Rodríguez et al. (2011a,b) on Reiki’s effect
on burnout did not allow any touch. Dressen and Singg (1998)
study only allowed touch for the head positions but not the body.
Vasudev and Shastri’s (2016) study found hands-on Reiki to be
significantly more effective than distant placebo Reiki (p= 0.028).
However, the hands-on Reiki was not significantly different from
the distant Reiki (p= 0.878), which used no sensory cues at all.
This suggests a placebo effect from relationship factors should not
have influenced outcomes. Relationship expectations influencing
the clients would also have been removed or reduced in the
two discussed RPCTs controlling for Criterion 2 (Shiflett et al.,
2002;Erdogan and Cinar, 2016). These controlled for therapist
expectations, which are central to the relationship.
In sum, all the RPCTs controlled for Criterion 3 to some
extent, and eight RPCTs controlled for it to a larger extent
(Dressen and Singg, 1998;Shiflett et al., 2002;Bowden et al., 2010,
2011;Díaz-Rodríguez et al., 2011a,b;Erdogan and Cinar, 2016;
Vasudev and Shastri, 2016). Of these eight, six showed significant
therapeutic outcomes for Reiki over placebo. Erdogan and Cinar’s
(2016) study controlled for Criteria 1, 2, and 3 and found highly
significant effects for Reiki over placebo, although it still had
an ROB of some concerns and did not describe the blinding
procedure applied to the therapists.
Hamilton (2021) argues that Reiki’s effects are essentially
placebo by-products of criteria B and C, that is, the expectations
of the practitioners and the strength of the relationship. He
argues that the recipient becomes aware of the emotional states
of the real Reiki therapist through their facial expressions and
body language and that these are more convincing than the
sham Reiki therapist. He also argues that mirror neurons in the
brain, which make us mimic the therapist’s emotional states,
facilitate this emotional transference, which is enough to produce
a statistically significant impact of Reiki from a real therapist over
sham Reiki (Hamilton, 2021). This argument is not convincing
given the above discussion. As mentioned, in four RPCTs,
the participants were blindfolded and/or not touched by the
therapists to minimize or eliminate sensory cues. In two other
studies, practitioner expectations were controlled for, one of
which produced highly significant results.
Hamilton (2021) also argues that the therapist’s emotional
state affects their bioelectric current and magnetic field, which has
been shown to have the ability to influence another’s bioelectric
and magnetic fields. If this is correct, even without visual or
tactile cues, a real Reiki’s practitioner’s positive intention may
be what is influencing the client over sham Reiki practitioners
who have no genuine healing intention toward the client. This
possibility is worth considering. However, Erdogan and Cinar’s
(2016) RPCT provides evidence to the contrary. In their study,
the sham Reiki therapists were made to believe that they were
practicing real Reiki, which, according to Hamilton (2021), would
have therapeutically enhanced their bioelectric field and magnetic
current, thereby influencing the clients’ bioelectric field and
magnetic current as much as the real Reiki practitioners did.
However, the real Reiki practitioners still produced a therapeutic
effect that was highly statistically significant over the sham
practitioners despite having the same therapeutic expectations.
More well-controlled double-blind experiments are needed to
further verify this result. Such studies will also help isolate
underlying mechanisms of influence for Reiki. As mentioned at
the start of this article, studies that best control for all the placebo
Criteria A, B, and C are studies on Reiki’s influence on non-
human living systems: cell cultures, isolated cells, rats, and dogs,
and all found highly significant results compared with placebo
(Baldwin and Schwartz, 2006;Baldwin et al., 2008;Mothersill
et al., 2013;Kent et al., 2020;Pacheco et al., 2021).
Under What Parameters Is Reiki
Effective Over Placebo?
Clinically Relevant Baseline Scores
As discussed, the findings suggest that Reiki is more effective
than placebo when the baseline scores are clinically relevant
even if low. There may be other variables impacting energy
healing (Griffin and Erdreich, 1991;Oschman, 2015), such as
the size of a client’s biofield or the environment in which it is
practiced; however, this SR highlights the importance of clinically
relevant baselines.
Reiki Dosage
The RPCT perhaps showing the most benefit for Reiki in reducing
depression was by Erdogan and Cinar (2016), in which Reiki
was administered for a longer period of 45 to 60 min one time
a week for 8 weeks. However, Shore (2004) also administered
Reiki for long periods of 60–90 min one time a week for 6 weeks
but achieved moderate significance at post-test (p= 0.042). The
three RPCTs that produced non-significant results for depression
also applied Reiki 6 to 10 times, although for only 20 to 30 min
per application (Shiflett et al., 2002;Bowden et al., 2010, 2011).
Overall, these RPCTs suggest that 60 min of Reiki for 6 to
10 weeks may be sufficient to produce a significant therapeutic
effect for at least mild clinical depression over placebo with
potentially long-lasting effects.
For anxiety, the three RPCTs with significant findings all
administered 30 min of Reiki on three or more occasions
(Dressen and Singg, 1998;Baldwin et al., 2017;Çinar et al., 2022),
suggesting that at least four applications of at least 30 min of Reiki
one time a week may reduce anxiety compared with placebo.
For stress, Yüce and Ta¸scı (2021) (2021) administered 45 min
of Reiki one time a week for 6 weeks, producing highly
significant results in reducing stress when compared with placebo
(p= 0.001). Bowden et al. (2011) used six applications of 30 min
of Reiki again, resulting in highly significant results for stress
when compared with placebo (p= 0.008). Vasudev and Shastri
(2016), however, used very short applications of 5 min of Reiki
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per day but for 21 consecutive days, producing significant results
(p= 0.028) although not as high as the other studies using longer
treatment periods. Interestingly, Shore (2004), whose participants
had normal baseline scores for stress, also produced significant
results (p= 0.029). Shore (2004) used 60–90 min of Reiki for
over 6 weeks, and it may have been the longer treatment period
that produced significant results even in participants with normal
levels of stress. Overall, compared with placebo, at least six
sessions of at least 30 to 45 min of Reiki may reduce stress with
potentially long-term effects.
For health professionals diagnosed with burnout, two studies
found that a single 30-min session of Reiki can significantly
reduce biomarkers related to burnout in the short term (Díaz-
Rodríguez et al., 2011a,b). Another study by Rosada et al.
(2015) found that 30 min of Reiki one time a week for
6 weeks also significantly reduced burnout when compared
with placebo. These studies suggest that one 30-min session of
Reiki may benefit the biomarkers of those experiencing burnout
in the short term.
Type and Level of Training and Experience
Many Reiki practitioners consider that the level of training and
years of experience increase the flow of Reiki energy. Some
consider the type of Reiki training and how they were trained as
also important and advocate the original Usui method through
face-to-face training as preferred.
Of the 14 RPCTs, five used Reiki practitioners trained with
the original Usui method and of these, two studies stated that
they used a practitioner trained solely in the Usui method (Díaz-
Rodríguez et al., 2011a;Yüce and Ta¸scı, 2021). The other three
RPCTs stated that they used practitioners trained in the Usui
method and one or more in other healing methods (Shiflett et al.,
2002;Bowden et al., 2010, 2011). The remaining nine studies only
state that the practitioners used Reiki. Given the variation, it is
difficult to discern the impact of this variable.
Level of attunement and years of experience are also
considered important. Of the 14 RPCTs assessed, six stated
they used Reiki masters only (Thornton, 1991;Bowden et al.,
2010, 2011;Díaz-Rodríguez et al., 2011a,b;Erdogan and Cinar,
2016). Another three used Reiki masters in addition to either
level 2 practitioners (Shore, 2004;Rosada et al., 2015) or level
1 and 2 practitioners (Shiflett et al., 2002). One study used
only a level 2 practitioner (Yüce and Ta¸scı, 2021) and produced
highly significant results, suggesting level 2 training may be
sufficient for highly significant outcomes. Six studies stated
their practitioners’ years of experience (Thornton, 1991;Shore,
2004;Bowden et al., 2010, 2011;Díaz-Rodríguez et al., 2011a,b),
ranging from at least 1 year (Shore, 2004) to 15 years (Díaz-
Rodríguez et al., 2011a,b). From these outcomes, we might
conclude that an experienced level 2 practitioner or a Reiki
master with at least 4 years of experience could be used for
research purposes.
Challenges and Limitations of the
Evidence
All the areas under review had few studies, so the findings are
not conclusive. Several confounding variables other than the level
of wellness may also influence outcomes, such as dose, level and
type of training, years of practitioner experience, and whether
the practitioner was trained in other methods of energy healing
and had been trained in ways which may not be effective such as
being attuned at a distance. Some of the studies also did not blind
the assessors or make it clear whether the outcome assessors were
blinded, potentially biasing the outcomes.
Conclusions
In the area of mental health, so far, there is some evidence that
Reiki is consistently more effective than placebo in reducing
clinical symptoms of depression, anxiety, stress, and burnout.
This effect is observed by decreased symptoms, as measured by
validated outcome measures, or validated instruments in each of
the areas under study.
So far the research suggests that the duration and frequency
of Reiki required to obtain a therapeutic effect over placebo is as