The efficacy of "distant healing": a systematic review of randomized trials

To conduct a systematic review of the available data on the efficacy of any form of "distant healing" (prayer, mental healing, Therapeutic Touch, or spiritual healing) as treatment for any medical condition.

Studies were identified by an electronic search of the MEDLINE, PsychLIT, EMBASE, CISCOM, and Cochrane Library databases from their inception to the end of 1999 and by contact with researchers in the field.

Studies with the following features were included: random assignment, placebo or other adequate control, publication in peer-reviewed journals, clinical (rather than experimental) investigations, and use of human participants.

Two investigators independently extracted data on study design, sample size, type of intervention, type of control, direction of effect (supporting or refuting the hypothesis), and nature of the outcomes.

A total of 23 trials involving 2774 patients met the inclusion criteria and were analyzed. Heterogeneity of the studies precluded a formal meta-analysis. Of the trials, 5 examined prayer as the distant healing intervention, 11 assessed noncontact Therapeutic Touch, and 7 examined other forms of distant healing. Of the 23 studies, 13 (57%) yielded statistically significant treatment effects, 9 showed no effect over control interventions, and 1 showed a negative effect.

The methodologic limitations of several studies make it difficult to draw definitive conclusions about the efficacy of distant healing. However, given that approximately 57% of trials showed a positive treatment effect, the evidence thus far merits further study.