The Effects of Prayer on Recovery from Illness: A Randomized, Controlled Clinical Trial




Smith-Hansen, Lotte

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This study examined the effects of remote, intercessory prayer on a group of hospitalized cardiac patients who were unaware that they were prayed for. The purpose of the study was to conduct an independent replication of the study by W.S. Harris et al. (1999) which found positive effects of prayer. The study found no differences in hospitalization outcomes between the treatment group (N = 26) and the control group (N = 25), as assessed by number of days in the intensive care unit, number of days in the hospital, and overall “hospital course” operationalized as weighted scores on the MidAmerica Heart Institute Cardiac Care Unit instrument (a checklist of medications, procedures, and complications). If indeed intercessory prayer can affect recovery from illness, the limitations of the study may in part explain the lack of positive results. These limitations included insufficient statistical power; questionable validity and reliability of the MAHI-CCU scores; a low number of intercessors per patient; a lack of uniquely identifying information targeting the prayer to the patients in the treatment group; and possibly negative effects of the study itself on the quality of the prayers. Recommendations for future studies of prayer are discussed.



intercessory prayer, recovery, healing, clinical trials, illnesses


Smith-Hansen, L. (2004). The effects of prayer on recovery from illness: A randomized, controlled clinical trial (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.


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