Over the past three decades, a number of scientific studies have been undertaken by medical researchers to try to determine if intercessory prayers (or ‘distant therapies’, which include prayer) have any impact on the medical outcomes being prayed for (often recovery from an operation or medical intervention). The tables below summarises a number of these studies, and the conclusions of researchers who have drawn together the results of individual studies. For discussion of these studies, see can prayer assist healing?
Studies which found a positive response to prayer
| Date | Study | Size of sample | Result | Reference |
|---|---|---|---|---|
| 1965 | The objective efficacy of prayer: A double-blind clinical trail. Joyce and Welldon | 32 | Almost no difference, but some suggestions of positive effect | In Hodge (2007). |
| 1969 | The efficacy of prayer: A triple blind study. Collipp | 18 | Borderline significant improvements | In Hodge (2007). |
| 1988 | Positive Therapeutic Effects of Intercessory Prayer in a Coronary Care Unit Population. R Byrd, San Francisco Medical Center | 393 | “These data suggest that intercessory prayer to the Judeo-Christian God has a beneficial therapeutic effect in patients admitted to a CCU.” | July 1988. SOUTHERN MEDICAL JOURNAL. Vol. 81, No. 7. |
| 1997 | An experimental study of the effects of distant, intercessory prayer on self-esteem, anxiety, and depression. S O’Laoire | 496 | “Subjects improved significantly on all 11 measures.” | National Center for Biotechnology Information |
| 1998 | A Randomized Double-Blind Study of the Effect of Distant Healing in a Population With Advanced AIDS: Report of a Small Scale Study. F Sicher et al, Geraldine Brush Cancer Research Institute, California | 40 | “a positive therapeutic effect of distant healing” | Western Journal of Medicine |
| 1999 | Phase 1 (feasibility) of MANTRA (Monitoring and Actualization of Noetic TRAinings) Project. Duke Uni Medical Center | 150 | “Cardiac patients who received intercessory prayer in addition to coronary stenting appeared to have better clinical outcomes.” Note: Phase 2 (below) found no improvement. | Charity Wire |
| 1999 | A Randomized, Controlled Trial of the Effects of Remote, Intercessory Prayer on Outcomes in Patients Admitted to the Coronary Care Unit. Harris et al, Saint Luke’s Hospital, Kansas City | 990 | “Remote, intercessory prayer was associated with lower CCU course scores. This result suggests that prayer may be an effective adjunct to standard medical care.” | Archives of Internal Medicine |
| 2000 | Does prayer influence the success of in vitro fertilization-embryo transfer? Cha & Wirth, Cha Hospital, Seoul, South Korea. | 219 | “A statistically significant difference was observed for the effect of IP on the outcome of IVF-ET, though the data should be interpreted as preliminary.” Note: some doubts have been expressed about this study. | National Center for Biotechnology Information |
| 2000 | Effects of intercessory prayer on patients with rheumatoid arthritis. Matthews, Marlowe, and MacNutt | 40 | “Patients receiving in-person intercessory prayer showed significant overall improvement. No additional effects from supplemental, distant intercessory prayer were found.” | National Center for Biotechnology Information |
| 2000 | The efficacy of “distant healing”: a systematic review of randomized trials. Astin, Harkness & Schlitz, Uni of Maryland School of Medicine | Review of 23 trials | “57% of trials showed a positive treatment effect” | National Center for Biotechnology Information |
| 2000 | Effects of remote, retroactive intercessory prayer on outcomes in patients with bloodstream infection: randomised controlled trial. L Leibovici, Rabin Medical Center, Israel | 3393 | “Remote, retroactive intercessory prayer said for a group is associated with a shorter stay in hospital and shorter duration of fever in patients with a bloodstream infection and should be considered for use in clinical practice.” | National Center for Biotechnology Information |
| 2002 | Does prayer really help? Furlow & O’Quinn, Uni of Texas | 38 | “significantly shorter stays in the hospital” | Journal of Christian Nursing |
| 2003 | A systematic review of the quality of research on hands-on and distance healing: clinical and laboratory studies. Crawford, Sparber, Jonas, Samueli Institute for Information Biology, Alexandria, Va. | 90 studies | The majority (66%) of studies reported positive outcomes and 21% reported negative outcomes. Many methodological problems were found, but overall the studies were considered to be reasonably valid (internal validity of 75%). | PubMed, NCBI |
| 2004 | A Randomized Trial of the Effects of Remote Intercessory Prayer: Interactions with Personal Beliefs on Problem-Specific Outcomes and Functional Status. Palmer, Katerndahl & Morgan-Kidd, University of Texas | 86 | “No direct intervention effect on the primary outcomes was found. A marginally significant reduction [in several other outcomes].” | Journal of Alternative and Complementary Medicine |
| 2006 | The effect of intercessory prayer on wound healing in nonhuman primates. K Lesniak, Department of Psychology, Loma Linda University. | 22 | Prayer group animals recovered from wounds significantly better than the non-prayer group. | PubMed, NCBI |
| 2007 | A Systematic Review of the Empirical Literature on Intercessory Prayer. D Hodge, Arizona State University | Review of 17 studies | “prayer offered on behalf of another yields positive results” | NCBI. |
| 2010 | Study of the Therapeutic Effects of Proximal Intercessory Prayer (STEPP) on Auditory and Visual Impairments in Rural Mozambique. Candy Gunther Brown, Indiana University | 25 | “Subjects exhibited improved hearing and vision that was statistically significant after PIP [proximal intercessory prayer] was administered.” | Indiana University |
Studies which found no significant positive response to prayer
| Date | Study | Size of sample | Result | Reference |
|---|---|---|---|---|
| 1997 | Intercessory prayer in the treatment of alcohol abuse and dependence: A pilot investigation. Walker, Tonigan, Miller, Comer, and Kahlich | 40 | “No significant differences emerged between the experimental or the control group” | In Hodge (2007) |
| 2001 | Monitoring and Actualization of Noetic TRAinings (MANTRA) II study. Krucoff et al, Duke University Medical Center | 748 | “prayer made no significant difference to the long term health of the patients involved” (though a subgroup had significant improvements – Hodge) | Duke medicine. National Center for Biotechnology Information |
| 2001 | Intercessory prayer and cardiovascular disease progression in a coronary care unit population: a randomized controlled trial. Aviles et al, Mayo Clinic | 799 | “intercessory prayer had no significant effect on medical outcomes after hospitalization in a coronary care unit” (but some outcomes improved – Hodge) | National Center for Biotechnology Information |
| 2003 | Intercessory Prayer, Visualization, and Expectancy for Patients with Severe Illnesses: Implications for Pyschotherapy. W. J. Matthews, Conti, and Sireci | 95 | “the effects of intercessory prayer and transpersonal positive visualization cannot be distinguished from the effect of expectancy, and thus do not appear to be effective treatment interventions” | Questia |
| 2004 | Beneficial effects of noetic therapies on mood before percutaneous intervention for unstable coronary syndromes. Seskevich, Crater, Lane, & Krucoff | 150 | “prayer was unrelated to outcomes” | In Hodge (2007) |
| 2004 | Pilot study investigating the effect of intercessory prayer in the treatment of child psychiatric disorders. Mathai and Bourne | 33 | No difference in outcome | In Hodge (2007) |
| 2005 | Study of the Therapeutic Effects of Intercessory Prayer (STEP) in Cardiac Bypass Patients – A Multi-Center Randomized Trial of Uncertainty and Certainty of Receiving Intercessory Prayer. Benson et al, for the Templeton Foundation | 1802 | “Intercessory prayer itself had no effect on complication-free recovery from CABG, but certainty of receiving intercessory prayer was associated with a higher incidence of complications.” | Templeton Foundation |
| 2006 | Are there demonstrable effects of distant intercessory prayer? A meta-analytic review. Masters, Spielmans & Goodson | Review of 14 studies | “There is no scientifically discernable effect for IP as assessed in controlled studies.” | Annals of Behavioural Medicine |
| 2009 | Intercessory prayer for the alleviation of ill health. Roberts, Ahmed, Hall, Davison | Review of 10 studies | “due to various limitations in the trials included in this review …. it is only possible to state that intercessory prayer is neither significantly beneficial nor harmful for those who are sick.” | The Cochrane Collaboration |
Studies which found a positive response to prayer
Date: 1965
Study: The objective efficacy of prayer: A double-blind clinical trail. Joyce and Welldon
Size of sample: 32
Result: Almost no difference, but some suggestions of positive effect.
Reference: In Hodge (2007)
Date: 1969
Study: The efficacy of prayer: A triple blind study. Collipp
Size of sample: 18
Result:Borderline significant improvements
Reference: In Hodge (2007)
Date: 1988
Study: Positive Therapeutic Effects of Intercessory Prayer in a Coronary Care Unit Population. R Byrd, San Francisco Medical Center
Size of sample: 393
Result: “These data suggest that intercessory prayer to the Judeo-Christian God has a beneficial therapeutic effect in patients admitted to a CCU.”
Reference: July 1988. SOUTHERN MEDICAL JOURNAL. Vol. 81, No. 7.
Date: 1997
Study: An experimental study of the effects of distant, intercessory prayer on self-esteem, anxiety, and depression. S O’Laoire
Size of sample: 496
Result: “Subjects improved significantly on all 11 measures.”
Reference: National Center for Biotechnology Information
Date: 1998
Study: A Randomized Double-Blind Study of the Effect of Distant Healing in a Population With Advanced AIDS: Report of a Small Scale Study. F Sicher et al, Geraldine Brush Cancer Research Institute, California
Size of sample: 40
Result: “a positive therapeutic effect of distant healing”
Reference: Western Journal of Medicine
Date: 1999
Study: Phase 1 (feasibility) of MANTRA (Monitoring and Actualization of Noetic TRAinings) Project. Duke Uni Medical Center
Size of sample: 150
Result: “Cardiac patients who received intercessory prayer in addition to coronary stenting appeared to have better clinical outcomes.” Note: Phase 2 (below) found no improvement.
Reference: Charity Wire
Date: 1999
Study: A Randomized, Controlled Trial of the Effects of Remote, Intercessory Prayer on Outcomes in Patients Admitted to the Coronary Care Unit. Harris et al, Saint Luke’s Hospital, Kansas City
Size of sample: 990
Result: “Remote, intercessory prayer was associated with lower CCU course scores. This result suggests that prayer may be an effective adjunct to standard medical care.”
Reference: Archives of Internal Medicine
Date: 2000
Study: Does prayer influence the success of in vitro fertilization-embryo transfer? Cha & Wirth, Cha Hospital, Seoul, South Korea.
Size of sample: 219
Result: “A statistically significant difference was observed for the effect of IP on the outcome of IVF-ET, though the data should be interpreted as preliminary.” Note: some doubts have been expressed about this study.
Reference: National Center for Biotechnology Information
Date: 2000
Study: Effects of intercessory prayer on patients with rheumatoid arthritis. Matthews, Marlowe, and MacNutt
Size of sample: 40
Result: “Patients receiving in-person intercessory prayer showed significant overall improvement. No additional effects from supplemental, distant intercessory prayer were found.”
Reference: National Center for Biotechnology Information
Date: 2000
Study: The efficacy of “distant healing”: a systematic review of randomized trials. Astin, Harkness & Schlitz, Uni of Maryland School of Medicine
Size of sample: Review of 23 trials
Result: “57% of trials showed a positive treatment effect”
Reference: National Center for Biotechnology Information
Date: 2000
Study: Effects of remote, retroactive intercessory prayer on outcomes in patients with bloodstream infection: randomised controlled trial. L Leibovici, Rabin Medical Center, Israel
Size of sample: 3393
Result: “Remote, retroactive intercessory prayer said for a group is associated with a shorter stay in hospital and shorter duration of fever in patients with a bloodstream infection and should be considered for use in clinical practice.”
Reference: National Center for Biotechnology Information
Date: 2002
Study: Does prayer really help? Furlow & O’Quinn, Uni of Texas
Size of sample: 38
Result: “significantly shorter stays in the hospital”
Reference: Journal of Christian Nursing
Date: 2003
Study: A systematic review of the quality of research on hands-on and distance healing: clinical and laboratory studies. Crawford, Sparber, Jonas, Samueli Institute for Information Biology, Alexandria, Va
Size of sample: 90 studies
Result: The majority (66%) of studies reported positive outcomes and 21% reported negative outcomes. Many methodological problems were found, but overall the studies were considered to be reasonably valid (internal validity of 75%).
Reference: PubMed, NCBI
Date: 2004
Study: A Randomized Trial of the Effects of Remote Intercessory Prayer: Interactions with Personal Beliefs on Problem-Specific Outcomes and Functional Status. Palmer, Katerndahl & Morgan-Kidd, University of Texas
Size of sample: 86
Result: “No direct intervention effect on the primary outcomes was found. A marginally significant reduction [in several other outcomes].”
Reference: Journal of Alternative and Complementary Medicine
Date: 2006
Study: The effect of intercessory prayer on wound healing in nonhuman primates. K Lesniak, Department of Psychology, Loma Linda University.
Size of sample: 22
Result: Prayer group animals recovered from wounds significantly better than the non-prayer group.
Reference: PubMed, NCBI
Date: 2007
Study: A Systematic Review of the Empirical Literature on Intercessory Prayer. D Hodge, Arizona State University
Size of sample: Review of 17 studies
Result: “prayer offered on behalf of another yields positive results”
Reference: NCBI.
Date: 2010
Study: Study of the Therapeutic Effects of Proximal Intercessory Prayer (STEPP) on Auditory and Visual Impairments in Rural Mozambique. Candy Gunther Brown, Indiana University
Size of sample: 25
Result: “Subjects exhibited improved hearing and vision that was statistically significant after PIP [proximal intercessory prayer] was administered.”
Reference: Indiana University
Studies which found no significant positive response to prayer
Date: 1997
Study: Intercessory prayer in the treatment of alcohol abuse and dependence: A pilot investigation. Walker, Tonigan, Miller, Comer, and Kahlich
Size of sample: 40
Result: “No significant differences emerged between the experimental or the control group”
Reference: In Hodge (2007)
Date: 2001
Study: Monitoring and Actualization of Noetic TRAinings (MANTRA) II study. Krucoff et al, Duke University Medical Center
Size of sample: 748
Result: “prayer made no significant difference to the long term health of the patients involved” (though a subgroup had significant improvements – Hodge)
Reference: Duke medicine. National Center for Biotechnology Information
Date: 2001
Study: Intercessory prayer and cardiovascular disease progression in a coronary care unit population: a randomized controlled trial. Aviles et al, Mayo Clinic
Size of sample: 799
Result: “intercessory prayer had no significant effect on medical outcomes after hospitalization in a coronary care unit” (but some outcomes improved – Hodge)
Reference: National Center for Biotechnology Information
Date: 2003
Study: Intercessory Prayer, Visualization, and Expectancy for Patients with Severe Illnesses: Implications for Pyschotherapy. W. J. Matthews, Conti, and Sireci
Size of sample: 95
Result: “the effects of intercessory prayer and transpersonal positive visualization cannot be distinguished from the effect of expectancy, and thus do not appear to be effective treatment interventions”
Reference: Questia
Date: 2004
Study: Beneficial effects of noetic therapies on mood before percutaneous intervention for unstable coronary syndromes. Seskevich, Crater, Lane, & Krucoff
Size of sample: 150
Result: “prayer was unrelated to outcomes”
Reference: In Hodge (2007)
Date: 2004
Study: Pilot study investigating the effect of intercessory prayer in the treatment of child psychiatric disorders. Mathai and Bourne
Size of sample: 33
Result: No difference in outcome
Reference: In Hodge (2007)
Date: 2005
Study: Study of the Therapeutic Effects of Intercessory Prayer (STEP) in Cardiac Bypass Patients – A Multi-Center Randomized Trial of Uncertainty and Certainty of Receiving Intercessory Prayer. Benson et al, for the Templeton Foundation
Size of sample: 1802
Result: “Intercessory prayer itself had no effect on complication-free recovery from CABG, but certainty of receiving intercessory prayer was associated with a higher incidence of complications.”
Reference: Templeton Foundation
Date: 2006
Study: Are there demonstrable effects of distant intercessory prayer? A meta-analytic review. Masters, Spielmans & Goodson
Size of sample: Review of 14 studies
Result: “There is no scientifically discernible effect for IP as assessed in controlled studies.”
Reference: Annals of Behavioural Medicine
Date: 2009
Study: Intercessory prayer for the alleviation of ill health. Roberts, Ahmed, Hall, Davison
Size of sample: Review of 10 studies
Result: due to various limitations in the trials included in this review …. it is only possible to state that intercessory prayer is neither significantly beneficial nor harmful for those who are sick.”
Reference: The Cochrane Collaboration
A summary and discussion of these studies is at Can prayer assist healing?
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