1. ¹Department of Oncology, Aarhus University Hospital, 8000 Århus C, Denmark
2. ²Danish Healing Research Center, Stationsvej 16, 3210 Vejby, Denmark
3. ³Department of Dermatology, Copenhagen University Hospital, 2820 Gentofte, Denmark
4. ⁴Department of Biostatistics, Aarhus University, 8000 Århus C, Denmark

Correspondence: Professor R Zachariae, Psychooncology Research Unit, Christian Skous Vej 4, 8000 Århus C, Denmark. E-mail: bzach@as.aaa.dk

Received 23 May 2005; Revised 20 July 2005; Accepted 21 July 2005; Published online 23 August 2005.

Abstract

Alternative treatments such as spiritual healing and prayer are increasingly popular, especially among patients with life-threatening diseases such as cancer. According to theories of spiritual healing, this intervention is thought to influence living cells and organisms independently of the recipient's conscious awareness of the healer's intention. The aim of this study was to test the hypothesis that spiritual healing will reduce proliferation and viability of two cancer cell lines in vitro. Three controlled experiments were conducted with three different healers and randomised allocation of cells to five different doses of healing or control. Researchers conducting the assays and statistical analyses were blinded to the experimental conditions. Main outcome measures were MTT viability, ³H-thymidine incorporation and counts of an adherent human breast cancer cell line (MCF-7), and a nonadherent mouse B-lymphoid cell line (HB-94). Analyses of variance (ANOVAs) revealed no significant main or dose-related effects of spiritual healing compared to controls for either of the two cell lines or any of the assays (P-values between 0.09 and 0.96). When comparing healing and control across all three experimental days, doses, assays, and cells, 34 (51.6%) of 66 independent comparisons showed differences in the hypothesised direction (P=0.90). The average effect size across cell lines, days, assays, and doses approached zero (Cohen's d=-0.01). The results do not support previous reports of beneficial effects of spiritual healing on malignant cell growth in vitro. Reported beneficial effects of spiritual healing on the well-being of cancer patients seem more likely to be mediated by psychosocial and psychophysiological effects of the healer–patient relationship.