Healing as a therapy for human disease: A systematic review

Objective: To assess, from published clinical trials, the evidence for the use of healing as a complementary medical intervention in human disease. Design: Limited to studies involving random assignment to a treatment group consisting of "healing," broadly defined, or to a concurrent control group . All randomized trials published up to the year 2000, were identified from MEDLINE, CINAHL, BIDS-EMBASE, the CISCOM complementary medicine databases and from bibliographic references of published articles. Copies of all publ ished studies were obtained, data were extracted, and methodological qualit y (Jadad) scores were derived where possible. Results: Fifty-nine randomized clinical trials (RCTs) were found comparing healing with a control intervention on human participants. In 37 of these, healing was used for existing diseases or symptoms (22 existed as fully acc essible published reports, 10 as dissertation abstracts only, and 5 as "pre liminary" investigations with limited evidential value). The 22 full trials (10 reporting a "significant" effect of healing compared with control) constitute an extremely heterogeneous group, varying greatly in the method and duration of healing; the medical condition treated; the outcome measure employed; and the control intervention used. Many trials ha d a number of methodological shortcomings, including small sample sizes, an d were inadequately reported. Only 8 studies (5 with a significant outcome for healing) had a maximum methodological quality score of 5, and in 10 stu dies this score was 3 or less. Two trials-both large scale and methodologic ally sound-were replicates, and each found a significant beneficial effect of intercessory prayer on the clinical progress of cardiac patients. Eleven of the 15 dissertation abstracts and pilot studies reported nonsignificant results for healing compared with control, a finding that probably reflect s the relatively small. sample sizes and the likelihood of type II errors. The significant heterogeneity found in this group of trials makes categoriz ation problematic and inhibits the pooling of results by meta-analysis or s imilar techniques to obtain a global estimate of the "treatment effect" of healing. Conclusions: No firm conclusions about the efficacy or inefficacy of healin g can be drawn from this diverse group of RCTs. Given the current emphasis on evidence-based medicine, future investigations should be adequately powe red, appropriately controlled, and properly described. These future investi gations would most usefully consist of: (1) pragmatic trials of healing for undifferentiated conditions on patients based in general practice and (2) larger RCTs of distant healing on large numbers of patients with well-defin ed measurable illness.