We performed a Phase-II feasibility pilot study to determine which of four potential stress reduction interventions were acceptable, feasible, and potentially efficacious to proceed to a Phase-III efficacy trial. Each intervention was feasible and acceptable to Methodist clergy. Engagement was high across interventions with a majority of participants reporting engaging in intervention practice multiple days per week. Moreover, the range of effect sizes comparing interventions to control on symptoms of stress and stress reactivity encompassed thresholds for practical significance (mean difference > .41; 53). With the exception of Centering Prayer, the point estimate of effect for symptoms of stress and stress reactivity were at or below this threshold of practical significance which supports further examination in a Phase-III efficacy trial. The effect of interventions on HRV MESOR and amplitude were mixed with few interventions resulting in an appreciable change relative to control.
The primary reason to offer four different programming options to clergy was to discover which interventions they would find acceptable and feasible, and to identify barriers that might inform intervention redesign before proceeding to an adequately powered and resource-intensive trial. We allowed clergy to enroll in the intervention of their choosing, and we considered enrollment size to be an indicator of acceptability. Stress Proofing was the most popular, followed by the Daily Examen. Clergy may have been particularly attracted to Stress Proofing because it offered a two-night stay in a retreat center and few clergy had experience with its stress reduction practices. In contrast, all other interventions did not offer an overnight stay. Centering Prayer had the lowest enrollment, which may have been due to UMC clergy in North Carolina already having had opportunities to learn Centering Prayer through a non-profit organization and due to the slightly less desirable and accessible locations offered. Interview comments on acceptability across the interventions were strongly positive. Participants noted that the two spiritual practices matched their desired prayer life and helped them feel closer to God. Interestingly, one participant also commented that MBSR connected them to their body and that this had a desirable outcome of helping them consider how their body is used to serve God. No one mentioned this connection for Stress Proofing, which also sought to put people in touch with their bodies. Instead, one participant who completed Stress Proofing expressed a wish for spiritual content.
We allowed clergy of all physical health states to participate. United Methodist clergy have previously been documented having above-average rates of chronic diseases, including hypertension, diabetes, arthritis, angina, and asthma (1). An important question is whether participants at risk of chronic disease find a stress management intervention to be feasible. In the current study, all interventions appeared feasible for clergy. Regular practice of the Daily Examen appeared especially feasible, with 80.0% practicing it on at least half of the days across 12 weeks. MBSR had the lowest daily practice of the four interventions, with 42.9% practicing it at least half of the days, which is nevertheless a remarkable behavior change for many participants. MBSR practice is likely to yield good outcomes; of the four interventions tested, it has the most robust evidence base with prior outcome studies reporting reduced symptoms of anxiety (54, 55), reduced symptoms of depression (56), decreased stress (57), and improvement in sleep quality (58), and being effective among participants with high anxiety and poor sleep quality at baseline (59). We do not yet have a good understanding about the dose (i.e., frequency and number of minutes engaged in practice) needed to experience improvement in stress. In the current study, the number of minutes practiced (22.6) was lower than what MBSR outcome studies have tested. In one meta-analysis, the range of minutes practiced was 60-120 minutes (60). However, fewer minutes of daily practice may be beneficial. For example, Smith, Metzker (54) found decreased perceived stress, decreased anxiety, increased awareness, and increased acceptance with 15-25 minutes of daily practice.
A study objective was to identify changes to improve the interventions before proceeding to an adequately powered trial. We recommend offering an overnight stay to allow for travel time and enough calming space to practice stress management skills. For Stress Proofing, we recommend that clergy learn the skills without engaging in physical contact with one another, and incorporating reasonable spiritual concepts into activities, such as the sacredness breath. In addition, the Stress Proofing content was broad and heavily didactic; we recommend starting the workshop with an activity, being clearer on which activities to regularly practice, and cutting back on the amount of time spent teaching the physiology of stress. For Centering Prayer, some participants found it hard to sit for 20 minutes without distraction in a group setting, while others enjoyed practicing in a group; perhaps expectations could be set in advance. For the Examen, reports of the two post-workshop sessions using a web platform at 2 and 4 weeks later were highly positive; we recommend considering this structure across interventions.
We collected data on practice adherence using text messages. Although we were initially concerned that a daily text message would be perceived as annoying, participants nearly universally indicated that they welcomed the daily message as a reminder and accountability structure, such that even programs not interested in evaluation should consider including text messages. We recommend sending the message at noon and again at 4 pm for non-responders. We recommend personalizing the text messages with the participant’s name, and varying an intro message (e.g. “Peace be with you!” every few weeks.)
We collected outcome data on a small sample of participants in this pilot trial to determine the feasibility of trial procedures. We found that the 3-week survey assessment did not contribute much unique information, and that text messages were best sent daily, as opposed to every two days. We also used the outcome data to assess the likelihood of change in symptoms for each intervention, with particular interest in the spiritual practices because relatively few studies of spiritual practice interventions for stress reduction exist. For the Examen, we found promising changes in stress and anxiety symptoms and stress reactivity, but neutral to unfavorable changes for HRV. For Centering Prayer, we found promising change patterns for HRV and stress reactivity, but increased anxiety symptoms. In contrast, another study of Centering Prayer found decreased anxiety symptoms using a different measure for participants who practiced 20 minutes six times a week. Stress Proofing showed statistically significant improvements in stress reactivity and symptoms, which is consistent with other stress inoculation training intervention studies, for example among pregnant women who report reductions in perceived stress (61). However, Stress Proofing showed deteriorations in stress response based on the HRV measures. For future tests of Stress Proofing, we recommend increased focus on and motivation for the breathing and physical practices that can be incorporated multiple times per day. For MBSR, change patterns were consistently positive. As a point of reference, the decrease in anxiety symptoms was small (-2.0 points), but akin to other studies using the same anxiety measure as an outcome for MBSR interventions (3.4 points (54); 1.9 points (62)).
We evaluated the likelihood that interventions would produce change in symptoms of stress and stress reactivity. Interventions were considered promising and moved to full trial if the point estimate of effect was close to recommendations for minimum practically significant effects (i.e. mean difference ≥ 0.41; 53). Adopting these criteria, MBSR, Stress Proofing, and Examen were considered interventions with particular promise to improve stress management of clergy and proceeded to Phase-III efficacy testing in the ongoing Selah trial. The stress management interventions we evaluated produced less reliable change in long-term HRV parameters. RMSSD is an indirect indicator of the strength of the parasympathetic nervous system on heart rate and correlates well with high frequency HRV (63). We chose to include RMSSD given that it may serve as a proximal indicator for integration of brain mechanisms that guide flexible control over behavior with peripheral physiology and may provide an important window into understanding stress and health (64). Moreover, long-term measures of RMSSD have been associated with markers of stress at work among adults between 35 and 44 years of age (65). It has been recognized that perceived and objective measures of stress assess different aspects of the psychobiological sequelae that is stress, with multi-method assessments being favored (66). We will use multi-method assessments, including RMSSD, in the trial, but the sample size was not large enough in this pilot study to use RMSSD measures to inform which interventions to proceed to trial.
This study has several limitations, most notably the small sample size of the control and intervention groups. The control participants experienced some changes in outcomes despite not receiving an intervention, which may be attributable to expectancy effects, or carry-over effects between clergy enrolled in intervention groups. Timing of measurement of the control condition differed than that of the experimental condition with Time 3 assessment occurring at 8 weeks opposed to 12 weeks. This was a pragmatic decision that may impact the results observed. We recruited a convenience sample of clergy; our sample may lack the full diversity of clergy experiences. Findings are most generalizable to United Methodist clergy but may be relevant to clergy of other Christian denominations. We did not randomly assign participants to intervention arms because we believe that participant preference is important to sustain daily stress reduction practices. This introduces selection bias into intervention arms and conflates intervention effects with expectancy effects. As such, results must be interpreted in comparison to the control group or within intervention arm rather than between arms. Study strengths include collecting a variety of kinds of acceptability and feasibility data, collecting survey and physiological data, collecting daily participation data for 12 weeks, and including a control group.
In conclusion, the current study reports on Phase II preliminary testing of four potential stress reduction interventions, including two under-studied spiritual practices that may align with the values and thus preferences of Christian clergy and individuals. All four interventions were acceptable and feasible for clergy, and have the potential of appealing to busy professionals who are called to their work more broadly. The preliminary testing reported here is critical to inform trial conduct, enhance intervention redesign, and improve resource expenditure by ensuring that only well-informed interventions proceed to Phase III efficacy trials, including the Selah Phase III trial.