Effects of Reiki therapy on quality of life: a meta-analysis of randomized controlled trials

Abstract

Purpose

This review aimed to evaluate the therapeutic effects of Reiki therapy on quality of life.

Methods

The review followed standard scientific journal practices and a systematic search of PubMed, Web of Science, Embase, Scopus, and the Cochrane Library, with a literature cutoff of September 2024, was conducted to identify relevant studies. Inclusion criteria comprised articles published in English, randomized controlled trials (RCT), Reiki therapy as the independent variable, diverse patient populations, and outcome measures focusing on quality of life improvement.

Results

The review involved 661 participants aged 14 years and above, showing a significant enhancement in quality of life post-Reiki therapy (SMD = 0.28, 95% CI 0.01 ~ 0.56, P = 0.043). The subgroup analysis showed that Reiki therapy interventions with a frequency of ≥ 8 sessions and a duration of ≥ 60 min and acute interventions of ≤ 20 min were most effective in improving quality of life.

Conclusions

The existing meta-analysis and systematic review suggested that Reiki therapy positively impacted quality of life. Therefore, it was recommended that patients with cancer, surgical patients, chronic illnesses, and the general population receive acute Reiki therapy sessions (≤ 20 min) or Reiki therapy with sufficient frequency (≥ 8 sessions) and duration (≥ 60 min) to enhance their quality of life.

Systematic review registration

Systematic review registration: PROSPERO CRD 42023483961.

Introduction

Quality of life (QOL) is a multifaceted concept encompassing an individual's overall health, comfort, and ability to engage in and enjoy life [1]. In healthcare, QOL is viewed as multidimensional, incorporating emotional, physical, material, and social well-being. The Euro QOL 5D (EQ-5D) is a commonly used tool to assess QOL, focusing on mobility, self-care, daily activities, pain/discomfort, and anxiety/depression [2]. Factors like stress, anxiety, fatigue, and depression have a direct impact on an individual's well-being. Research shows that pain, stress, and emotional effects caused by illness can significantly reduce a patient's quality of life [3].

Reiki therapy is a complementary healthcare approach where practitioners gently place their hands on or above a person’s body to guide energy and promote the individual's healing response [4]. This therapy is rooted in an Eastern belief in life force energy that supports the body's innate healing capabilities. Reiki has shown no harmful effects compared to other complementary and alternative therapies like herbal medicine, dietary supplements, and massage therapy [5]. Originating in Japan in the early twentieth century by Mikao Usui, Reiki is a non-invasive, non-manipulative relaxation therapy using light touch. Practitioners typically place their hands lightly above or on the clothed body of the recipient, following a series of hand positions to gently stroke their front and back. Importantly, Reiki is not affiliated with specific religious beliefs and is embraced by individuals from diverse backgrounds and belief systems [6]. Initially, Reiki was primarily utilized for postoperative patients, individuals with cancer, and those with depression to alleviate anxiety, stress, and fatigue, aiming to reduce suffering and enhance overall quality of life. As experts and users from various fields acknowledged the positive effects of this therapy, its applications broadened to the general population. Simultaneously, with the high costs and potential side effects associated with traditional drug treatments, non-invasive therapies like therapeutic touch, Qigong, and Reiki as energy therapies have gained popularity for pain relief, anxiety reduction, fatigue management, and stress alleviation [7]. Reiki therapy has demonstrated effectiveness in reducing pain intensity, anxiety levels, and analgesic demands following cesarean section, positioning it as a potential complementary or non-pharmacological intervention for pain and anxiety relief post-surgery [8]. Despite its increasing utilization in clinical settings to alleviate pain and enhance the quality of life [9,10,11], there remains skepticism among scholars regarding its efficacy. The National Center for Complementary and Integrative Health (NCCIH) has highlighted a lack of robust clinical studies supporting the health benefits of Reiki, questioning the existence of the energy field associated with this practice [11]. Nonetheless, a body of research and meta-analyses has suggested that Reiki therapy offers benefits beyond initial doubts, including improvements in quality of life and reductions in stress and anxiety [6, 12,13,14,15]. While previous systematic reviews have explored Reiki’s impact on pain management [16], a comprehensive assessment and meta-analysis of its effects on diverse patient populations and its role in enhancing quality of life are still lacking. This review aims to fill this gap by examining the positive outcomes of Reiki therapy on quality of life, offering fresh insights and potential solutions to contemporary health challenges.

Materials and methods

Study design

This review was a systematic review of randomized controlled trials (RCTs), conducted using the PRISMA 2020 guidelines. The PRISMA 2020 statement was a guideline that aimed to improve the reporting quality of systematic reviews and meta-analyses [17]. The review protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) before screening the search results (Registration number: CRD 42023483961), following the PRISMA statement.

Study inclusion criteria

The inclusion and exclusion criteria for the literature reviewed in this review were established in line with the PICOS principles, with the key points summarized as follows:

• (1) The study population included surgical patients, cancer patients, normal adults, and normal children, all of whom had reduced quality of life due to various causes;

• (2) Included studies were required to have an intervention group and a control group, with the intervention group comprising participants who received Reiki therapy intervention and the control group consisting of participants who did not receive any intervention treatments or who were subjected to a sham Reiki therapy intervention;

• (3) Included studies had to evaluate quality of life using standardized scales written in English and accessible in full text;

• (4) The experimental design must have been a randomized controlled trial (RCT), with a minimum of one intervention session, including either a control or a sham Reiki therapy group;

• (5) Excluded studies included those not written in English, descriptive reviews, preclinical studies, duplicate studies, editorials, opinion articles, grey literature, and conference papers. Systematic reviews and study protocols that did not meet the criteria were also excluded, but relevant systematic reviews were consulted as guidelines and were appropriately cited.

Search strategy

This meta-analysis aimed to assess the efficacy of Reiki therapy in interventions targeting the enhancement of quality of life. A systematic search was conducted in PubMed, Web of Science, Embase, Scopus, and the Cochrane Library, with a literature cutoff date set at September 2024, to identify relevant studies. The search terms included “Reiki therapy” OR “Reiki intervention” AND “Quality of life” AND (“Controlled Trial” OR “Randomized Controlled Trial” OR “Clinical Trial” OR “Controlled Study” OR “Comparative Study” OR “Placebo-Controlled Trial”). Only full-text articles were considered, and their bibliographies were reviewed for additional relevant studies, with access to non-open access articles facilitated through payment.

Study selection process

The search results were imported into Zotero 6.0. After removing duplicates, two reviewers independently screened the titles and abstracts of the studies to exclude those not meeting the eligibility criteria. Full texts of all relevant studies were obtained, downloaded, and further assessed for eligibility. Any discrepancies in decisions to include certain studies were resolved through consultation between the two reviewers or with a third independent reviewer to minimize bias. Data extraction was independently performed by two reviewers, with discrepancies resolved through consultation with the aforementioned third independent reviewer.

Data extraction

The selected studies underwent analysis to extract data from various domains, such as author, year, sample size, participant age and gender, design, intervention description (including method, frequency, duration, and main components), control group, outcome measures, and time points, results, dropout rates, and handling of missing data.

Effect size measurement

The results from the included studies highlighted the average differences between the intervention group and the control group at the assessment endpoints. Data extraction and recording were independently conducted by two authors, with any discrepancies being resolved through consensus or consultation with a third reviewer. Studies were only considered for inclusion in the meta-analysis if the quality of life scale was adequately reported.

Data synthesis

Utilizing the Der Simonian-Laird random-effects and fixed-effects models, depending on the presence of heterogeneity, we conducted an analysis using STATA software (version 15) to determine the weighted average differences between the Reiki treatment group and the control group. The 95% confidence intervals (CI) were also calculated. The effect size estimates were weighted by the reciprocal of their variance, and Hedges’ g statistic was employed to calculate the effect size of standardized mean differences along with their respective 95% CIs. Interpretation of the Hedges’ g sizes considered values of 0.3 as small, 0.5 as medium, and 0.8 as large. To assess whether all studies evaluated the same effect under the null hypothesis, a chi-square test was conducted. The inconsistency index (I²) quantified the total variation in heterogeneity across studies, with values ranging from 0 to 100%. A P-value < 0.10 for the chi-square test and I² > 50% were considered significant indicators of heterogeneity [18]. To evaluate potential publication bias, a funnel plot was used with effect sizes from each trial plotted against standard errors. Any asymmetric findings in the funnel plot were further assessed using the Egger small-sample effect test based on regression.

Risk of bias (quality) assessment

The quality of each study was assessed using the Cochrane risk-of-bias tool for randomized trials, which evaluates aspects such as random sequence generation, allocation concealment, blinding of participants and personnel, blinding of outcome assessment, incomplete outcome data, selective reporting, and other biases [19]. Two independent authors conducted the quality assessments, with any discrepancies resolved by a third independent reviewer.

Results

Basic features included in the study

Initially, a total of 164 pieces of English literature were retrieved. After removing duplicates, 30 pieces of literature were excluded. Following a review of the titles and abstracts, 84 literature were obtained. After a thorough examination of the full text, 11 pieces of literature were included for Meta-analysis [9,10,11, 13,14,15, 20,21,22,23,24]. The literature screening process is shown in Fig. 1, and the basic characteristics of the included literature are shown in Table 1.

Fig. 1

Flow diagram of the selection process

Table 1 Characteristics of the studies in the systematic review and meta-analysis

Quality of included literature

All studies included in this analysis provided comprehensive descriptions of the generation of random allocation sequences and indicated a low risk of selection bias related to the generation of random allocation sequences [9,10,11, 13,14,15, 20,21,22,23,24]. However, the nature of these trials made blinding challenging for participants or Reiki therapists when considering performance bias. In Reiki intervention studies, blinding of outcome assessments is crucial for trial allocation. Nonetheless, four studies did not provide clear or specified measures for blinding outcome assessments [13, 14, 22, 24]. The assessment of attrition and reporting bias had been significantly influenced by these two studies [13, 22]. A summary and a graph of the risk of bias were provided in Fig. 2, respectively.

Fig. 2

Risk of bias graph

Study characteristics

Table 1 presents a comprehensive summary of the key attributes of the studies included in this meta-analysis. The meta-analysis consists of 11 randomized controlled trials (RCTs) with a total of 661 participants. These studies specifically investigated the impact of Reiki therapy on stress reduction, fatigue alleviation, and improvement in quality of life. The evaluation of the selected studies takes into account multiple factors such as research objectives, study characteristics, outcome measures, and significant findings.

Meta-analysis

This review systematically evaluated the effects of Reiki therapy on improving the quality of life. The analysis included 11 studies with a total of 661 participants [9,10,11, 13,14,15, 20,21,22,23,24]. The analysis revealed a significant level of heterogeneity (I² = 65.1%, P = 0.001), prompting the utilization of a random-effects model. Results demonstrated a marked enhancement in the quality of life among individuals who received Reiki therapy in comparison to the control group (SMD = 0.28, 95% CI 0.01 ~ 0.56, P = 0.043). Detailed data are shown in Fig. 3. Given the I² value exceeding 50% (I² = 65.1%, P = 0.001), an Egger regression was conducted to investigate potential publication bias. Egger’s test showed that there was no publication bias in the funnel plot, and the statistical analysis results were t = 0.29, P = 0.777 > 0.05, indicating that publication bias was no longer present. The publication bias of the included studies is shown in Fig. 4.

Fig. 3

Forest map of improved quality of life with Reiki therapy

Fig. 4

Quality of life publication bias graph

Subgroup analysis

To further investigate the heterogeneity of inter-study intervals (I² = 65.1%), the literature was subdivided into three subgroups based on subject types: cancer patients, surgical patients, and normal population. Subgroups were also formed based on exercise times (≤ 20 min, 30 min, 40–45 min, ≥ 60 min), total number of interventions (4 times, 5 times, 6 times, 7 times, and 8 times), intervention mode(the control group with an intervention, the control group had no intervention), and intervention time (≤ 1 week, 4 weeks, 6 weeks). The subgroup analysis showed that Reiki therapy interventions with a frequency of ≥ 8 sessions and a duration of ≥ 60 min and acute interventions of ≤ 20 min were most effective in improving quality of life. For more detailed information, please refer to Table 2.

Table 2 Static subgroup results analysis table

Discussions

Based on the analysis and extracted data, our review included 11 studies with a total of 661 subjects (n = 661). The results indicated that Reiki therapy significantly improved quality of life interventions (SMD = 0.28, 95%CI 0.01 ~ 0.56, P = 0.043). Subgroup analyses showed that the frequency of Reiki therapy interventions of ≥ 8 sessions, duration of ≥ 60 min, and duration of acute interventions of ≤ 20 min were significant factors influencing the improvement of heterogeneous factors for quality of life improvement in different populations. Quality of life showed significant improvement in cancer patients, chronic disease patients, and healthy individuals with a frequency of ≥ 8 sessions and a duration of ≥ 60 min, as well as acute interventions of ≤ 20 min. Rosenbaum and Velde conducted a study on cancer patients, finding that Reiki therapy, along with massage and yoga interventions, significantly improved quality of life by 31% (P < 0.001) [25]. In a similar vein, Alancar and Fonseca carried out a randomized controlled trial comparing patients who received Reiki treatment to those who received sham Reiki treatment twice a week over 4 weeks [20]. Their analysis revealed that Reiki therapy, as an adjunct intervention, effectively reduced pain and anxiety in oncology patients, leading to enhanced life satisfaction. Furthermore, a correlation between quality of life and fatigue was identified, suggesting that chronic disease-related fatigue could potentially impact overall quality of life. A study by Shirani et al. revealed that Reiki therapy interventions significantly improved the quality of life in patients with bone and joint diseases (P = 0.009) [23]. Similarly, Lee et al. demonstrated the positive impact of Reiki therapy on patients with severe gastrointestinal diseases after a treatment duration of more than 12 weeks [26]. Conversely, Pedersen et al. focused on colorectal cancer patients and determined that Reiki therapy did not significantly enhance their quality of life (P = 0.156) with a frequency of 4 sessions, suggesting a minimum intervention level is necessary for noticeable effects [11]. In a study by Dyer et al., Reiki therapy interventions on frontline healthcare workers during the COVID-19 pandemic resulted in significant improvements in health-related quality of life indicators, including reductions in stress, anxiety, and pain scores, as well as enhancements in well-being and sleep quality [22]. In summary, Reiki therapy functions as an effective complementary intervention that significantly enhances the quality of life for cancer patients, individuals with chronic conditions, and healthy adults by alleviating anxiety, stress, pain, and other adverse states. However, contradictory findings have emerged; one study on Reiki intervention for rectal cancer patients did not show a significant improvement in quality of life. These results imply that the duration and frequency of Reiki therapy interventions may be critical factors influencing its efficacy.

Subgroup analysis revealed a significant impact on quality of life improvement with Reiki therapy interventions lasting less than or equal to 20 min or longer than 60 min. Shirani et al. found that just 20 min of distant Reiki was equally effective in reducing pain and enhancing the quality of life for osteoarthritis patients compared to other forms of Reiki [23]. In a study by Zilda Alaração, the effects of Reiki therapy on the quality of life of leukemia patients were investigated. The subjects were randomly allocated into a true Reiki group and a sham Reiki group, each consisting of 58 participants [20]. The interventions lasted for 4 weeks, with each session lasting 60 min. The author concluded that Reiki was a beneficial and safe therapy for improving the quality of life of leukemia patients. One study by Olson et al. reported a significant increase in psychological component scores on a quality of life scale after a 7-day, 1-h per day Reiki intervention (+ 15%, P = 0.002) [27]. Denisse Gálvez Escudero’s research focused on the effects of regular Reiki therapy on 33 Peruvian employees in Lima who were dealing with COVID-19-related stress and anxiety. The study involved Reiki sessions twice a week for 3 weeks, showing that Reiki was beneficial for stress and anxiety relief [28]. Another study examined the use of Reiki therapy on healthy college students, with sessions held twice a week for 4 to 6 weeks. The results indicated that the group receiving Reiki therapy experienced a significant improvement in health status compared to the control group [29]. Overall, our comprehensive analysis, supported by relevant studies, suggests that subjects undergoing Reiki therapy more than 8 times may experience a noticeable enhancement in their quality of life.

Reiki therapy has been validated through numerous studies for its positive effects on the quality of life across various populations. However, the underlying mechanisms by which Reiki therapy exerts a significant impact on improving the quality of life in different groups warrant careful consideration and further research. Reiki therapy is classified as a non-invasive, non-manipulative relaxation technique within complementary medicine, utilizing a series of light touch or non-touch methods to gently engage with the recipient’s front and back, thereby guiding the flow of life energy to facilitate healing. As such, Reiki can be regarded as an energy therapy that influences specific energy fields within the body, playing a crucial role in enhancing the quality of life for diverse populations. A study has demonstrated that Reiki promotes relaxation and healing responses, thereby enhancing health-related quality of life [22]. These positive effects are evident in reductions of pain, anxiety, and fatigue [30]. Furthermore, the mechanism of Reiki therapy involves the overall balance of life energy, which enhances physical, emotional, mental, and spiritual well-being [31]. The improvement in quality of life resulting from Reiki therapy is also supported by changes in physiological indicators. Research indicates that Reiki therapy functions by promoting relaxation [32, 33], which is mediated by the parasympathetic nervous system [34], potentially leading to reduced inflammation [35]. Another study found that Reiki can decrease physiological markers of stress and inflammation [36, 37], such as reduced heart rate, lower blood pressure, and increased levels of salivary immunoglobulin A. Although the precise physiological mechanisms underlying the enhancement of quality of life through Reiki therapy remain unidentified, a synthesis of existing research suggests that it improves the quality of life by alleviating stress, pain, anxiety, and other adverse symptoms. The systematic analysis conducted in this review, supported by relevant literature, indicates that Reiki therapy has the potential to significantly enhance quality of life. Specifically, interventions comprising eight or more sessions of at least 60 min each, alongside acute interventions lasting 20 min or less, yielded the most substantial positive effects among cancer patients, chronically ill individuals, and healthy participants. Despite some heterogeneity in the results of certain studies, the overall findings suggest that Reiki therapy serves as a safe and effective complementary intervention for alleviating negative states such as anxiety, stress, and pain. Nonetheless, further high-quality randomized controlled trials (RCTs) are necessary to explore the optimal intervention parameters for Reiki therapy and to investigate its underlying physiological mechanisms.

Conclusions

Systematic evaluations have consistently demonstrated that Reiki therapy significantly enhances quality of life (QOL). Subgroup analyses further indicate that the therapy is most effective in improving QOL when administered with a high frequency of sessions (≥ 8) and extended duration (≥ 60 min), or in acute settings with sessions lasting up to (≤ 20 min). Consequently, it is recommended that individuals suffering from cancer, undergoing surgery, managing chronic conditions, and the general public consider Reiki therapy, either through short-term acute treatments (≤ 20 min) or through a regimen of sufficient frequency and duration (≥ 8 sessions, each lasting ≥ 60 min) to effectively enhance their quality of life.

Limitations

While some studies have indicated that the psychological impact of Reiki therapy on improving quality of life may not be statistically significant (P > 0.05) [20], others have suggested that systematic Reiki treatment could result in a notable improvement in the psychological well-being of patients and a positive shift in emotional states [15, 27]. However, the reliability of research findings is often questioned due to the complex array of factors that can influence quality of life, such as economic status, family background, personal health, psychological well-being, and environmental conditions. Experts stress the importance of conducting more comprehensive clinical studies to gain a deeper understanding of the psychological changes observed in research [11]. Additionally, the subjective initiative, which involves active engagement in Reiki treatment programs, is recognized as a crucial factor that can impact therapeutic outcomes. Therefore, future research endeavors should delve into this aspect further by incorporating a wider range of relevant literature.