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Thornton (1991) Female Nurses Unpublished	State Anxiety p = 0.864 d = −0.16 Trait Anxiety p = 0.350 d = −0.12	Some concerns	- Unnecessary as others small also.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 Taşcı (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.
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.
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.