The effects of intercessory prayer, positive visualization, and expectancy on the well-being of kidney dialysis patients

Abstract

Context: Little replicable empirical evidence on the effectiveness of prayer is available.

Objective: To explore the effect of intercessory prayer, positive visualization, and outcome expectancy on a wide range of medical and psychological measures in critically ill patients.

Design: 2 x 3 (expectancy x treatment) factorial study.

Participants: 95 adult male and female volunteer hemodialysis subjects with end-stage renal disease from an outpatient clinic in Miami, Fla.

Intervention: Participants were randomly assigned to 1 of the 6 treatment conditions.

Main outcome measures: A total of 20 dependent measures (10 medically based and 10 psychological) were used to assess the subjects' overall well-being. Analysis of covariance was used to control for pre-treatment differences between groups.

Results: Subjects who expected to receive intercessory prayer reported feeling significantly better than did those who expected to receive positive visualization (F1.93 = 5.42; P < .02). No other statistically significant main effects or interactions were found for either expectancy, intercessory prayer, or positive visualization on the remaining dependent measures. Analysis of effect sizes on all dependent measures failed to indicate even a small magnitude of effect for intercessory prayer as contrasted with expectancy on the medical or psychological variables.

Conclusions: The effects of intercessory prayer and transpersonal positive visualization cannot be distinguished from the effect of expectancy. Therefore, those 2 interventions do not appear to be effective treatments.