PURPOSE: To systematically review the quality of published experimental clinical and laboratory research involving hands-on healing and distance healing between 1955 and 2001. DATA SOURCES: Studies were identified through comprehensive literature searches on spiritual healing in MEDLINE, PSYCH LIT, EMBASE, CISCOM, and the Cochrane Library from their inceptions to December 2001. STUDY SELECTION: We selected published randomized, controlled trials of spiritual healing (hands-on healing and distance healing) done in clinical and laboratory settings, all of which had been peer reviewed. DATA EXTRACTION: Independent quality assessment of internal validity was conducted on all identified studies using the comprehensive Likelihood of Validity Evaluation scale. Clinical and laboratory studies were analyzed separately and then subdivided into hands-on healing or distance healing interventions. RESULTS: A total of 45 laboratory and 45 clinical studies published between 1956 and 2001 met the inclusion criteria. Of the clinical studies, 31 (70.5%) reported positive outcomes as did 28 (62%) of the laboratory studies; 4 (9%) of the clinical studies reported negative outcomes as did 15 (33%) of the laboratory studies. The mean percent overall internal validity for clinical studies was 69% (65% for hands-on healing and 75% for distance healing) and for laboratory studies 82% (82% for hands-on healing and 81% for distance healing). Major methodological problems of these studies included adequacy of blinding, dropped data in laboratory studies, reliability of outcome measures, rare use of power estimations and confidence intervals, and lack of independent replication. CONCLUSIONS: When laboratory studies were compared to clinical studies in the areas of hands-on healing and distance healing across the quality criteria for internal validity, distance healing studies scored better than hands-on healing studies, and laboratory studies fared better than clinical studies. Many studies of healing contained major problems that must be addressed in any future research.
PURPOSE: To systematically review the quality of published experimental clinical and laboratory research involving hands-on healing and distance healing between 1955 and 2001. DATA SOURCES: Studies were identified through comprehensive literature searches on spiritual healing in MEDLINE, PSYCH LIT, EMBASE, CISCOM, and the Cochrane Library from their inceptions to December 2001. STUDY SELECTION: We selected published randomized, controlled trials of spiritual healing (hands-on healing and distance healing) done in clinical and laboratory settings, all of which had been peer reviewed. DATA EXTRACTION: Independent quality assessment of internal validity was conducted on all identified studies using the comprehensive Likelihood of Validity Evaluation scale. Clinical and laboratory studies were analyzed separately and then subdivided into hands-on healing or distance healing interventions. RESULTS: A total of 45 laboratory and 45 clinical studies published between 1956 and 2001 met the inclusion criteria. Of the clinical studies, 31 (70.5%) reported positive outcomes as did 28 (62%) of the laboratory studies; 4 (9%) of the clinical studies reported negative outcomes as did 15 (33%) of the laboratory studies. The mean percent overall internal validity for clinical studies was 69% (65% for hands-on healing and 75% for distance healing) and for laboratory studies 82% (82% for hands-on healing and 81% for distance healing). Major methodological problems of these studies included adequacy of blinding, dropped data in laboratory studies, reliability of outcome measures, rare use of power estimations and confidence intervals, and lack of independent replication. CONCLUSIONS: When laboratory studies were compared to clinical studies in the areas of hands-on healing and distance healing across the quality criteria for internal validity, distance healing studies scored better than hands-on healing studies, and laboratory studies fared better than clinical studies. Many studies of healing contained major problems that must be addressed in any future research.