Design
This was a cross-sectional study with within- and between-subject assessments. Participants provided measures at baseline (non-stressful, group work condition), thereby acting as their own control, and prior to summative assessments (stressful condition) at the end of year 2.
Participants
Eligible participants were undergraduate medical students recruited from three cohorts commencing Year 1 studies on three consecutive years (2014 to 2016). Inclusion criteria were: aged over 18 years of age (no upper age limit), students enrolled on an undergraduate medical training program, and were in their second year of study. All participants were introduced to mindfulness in Year 1 as part of their training and encouraged to adopt the practice, although this was entirely optional. Participation was voluntary, with written informed consent obtained, with 122 students participating in the study and 67 students completing all parts of the study (8 from the 2014 cohort, 40 from the 2015 cohort, and 19 from the 2016 cohort).
Procedure
At the end of Year 2, participants who consented were approached during a standard group work session in term time (non-stressful condition) and provided a saliva sample and a rating of their current stress level. After which a demographic questionnaire and the Five Facet Mindfulness Questionnaire-Short Form were administered. Following this, prior to summative assessments (stressful condition) at the end of terms Year 2, students provided another rating of their current stress level, and a saliva sample. Examinations were written short answer papers, based on 12 clinical vignettes, with a possible ten marks available per vignette. Scenarios are based upon common presentations a student would be expected to see in practice. Upon completion of the study, participants were provided with a debrief letter detailing the study and reminding them of their right to withdraw until data were anonymized for analysis.
Measures
Demographic Characteristics
Of the 67 participants that provided complete data (i.e. baseline and pre-exam measures of perceived stress and saliva samples), 27 (40.3%) were male and 61 (91%) were single. The sample was diverse in ethnicity; 28.4% of the sample were white, 44.8% were Asian, and 13.4% were black/Caribbean/African. Detailed participant characteristics can be found in table 1. Independent-samples t-tests were conducted at baseline to compare the influence of demographic characteristics on mindfulness, baseline stress and cortisol, pre-exam stress and cortisol, and exam results. There were no significant differences in gender across these outcomes (p > .05). There were also no significant differences between those who had any previous experience of mindfulness and those who had none.
Table 1. Participant demographics.
|
|
N
|
%
|
Gender
|
Male
Female
|
27
40
|
40.3
59.7
|
Age
|
18-20
21-24
25-29
30-34
35-39
|
23
30
9
4
1
|
34.3
44.8
13.4
6.0
1.5
|
Marital status
|
Single
Married
Cohabiting
|
61
2
4
|
91.0
6.0
3.0
|
Ethnicity
|
White
Mixed/multiple
Asian
Black/Caribbean/African
Other
|
19
4
30
9
5
|
28.4
6.0
44.8
13.4
7.5
|
Perceived Stress: Prior to examinations, students were asked to provide a stress rating on a scale from 0-10, with 0 representing no stress at all, 5 representing moderate stress, and 10 representing stress as bad as it could be.
Salivary Cortisol: Participants were instructed to place a cotton swab underneath their tongue for one minute and then transfer the swab to a centrifugation tube with a filter insert. Immediately following collection, samples were spun down for 15 minutes at 25,000 RPM in a centrifuge held at 4̊C before being frozen at -80̊C until analysis. Analysis was conducted by ELISA as per the manufacturer’s instructions (cat # 1-3002, Salimetrics, Carlsbad, California, USA) for salivary cortisol measurement.
Five Facet Mindfulness Questionnaire-Short Form (FFMQ-SF; Bohlmeijer, ten Klooster, Fledderus, Veehof, & Baer, 2011): The FFMQ-SF consists of 24 items scored on five-point Likert scales ranging from 1 (never/rarely true) to 5 (very often/always true). It measures five factors representing elements of mindfulness: observing, describing, acting with awareness, non-judging of inner experience, and non-reactivity to inner experience, thus analyses can demonstrate which skills are important predictors of symptom reduction. Facet scores range from 5 to 25, apart from the facet of observing, which ranges from 4 to 20. The total maximum score on the FFMQ-SF is therefore 120, with higher scores indicating greater levels of mindfulness. The FFMQ-SF has strong psychometric characteristics, including good reliability with alpha coefficients above a = 0.70 for all facets The FFMQ-SF demonstrated a reliability of a = 0.70 in the present study indicating good reliability [26].
Statistical Methods
Data from two published meta-analyses of research involving the assessment of outcome measures in association with mindfulness [27, 28] concluded that studies involving mindfulness produce mean effect sizes of 0.59 and 0.54, respectively (considered medium sizes, according to Cohen’s (1988) criteria [29]. Based on this, an a priori power calculation was undertaken to establish the sample size required; based on a medium effect size = 0.50, alpha = 0.05 and confidence level = 0.95, the sample size required was n = 45, protecting against Type I error. Data were analyzed using Prism 9.1.2. 26.
Data were initially examined for distribution normality and outliers. Baseline and pre-exam salivary cortisol concentration and Perceived Stress scores are presented as means ± SEM standard error and statistically compared by Student’s t-test. Correlations were calculated between baseline measures and end point measures by Spearman’s rank correlation test.
Ethical Considerations
This study was approved by the University School of Science and Medicine Ethics Committee. All students gave their prior written consent for participation in the study and publication of results. So that the data collected were valid and therefore reflective of real life stressors in a medical students’ life, written examinations were utilised as stressors for this study. However, efforts were made to minimise the time commitment required of participants before examinations, and to ensure that participation in the study did not induce further stress, nor adversely affect examination performance. In line with this, participants were briefed prior to taking part in the study, and the time taken to complete assessments before examinations was reduced to a maximum of ten minutes.