Warnecke 2011.

Study characteristics
Methods	Study design: RCT Study grouping: parallel group Unit of randomisation: individuals Power (power & sample size calculation, level of power achieved): target sample size for the trial was 42 students per group (control and intervention); This number is based on data from a previous study of university students, which found a mean pre‐test PSS score of 18.11 (SD 6.19). These data are consistent with findings from the small unpublished pilot trial undertaken in our cohort last year. The trial was powered to detect a 4‐point difference (SD 0.6) in PSS score, using a 2‐tailed test, α = 0.05 and power = 0.80, and allowing for a 10% dropout rate. The cohort from which we recruited our participants numbered 194 students Imputation of missing data: no imputation of missing data specified (missing data treated as absent and were not assigned a score; no participants excluded from analysis); according to authors intention‐to‐treat analysis; based on outcome data received from authors (24 analysed in IG, 32 analysed in CG): available‐case analysis
Participants	Country: Australia Setting: guided mindfulness practice using CD; home setting Age: mean = 23.92 (SD = 3.2) years Sample size (randomised): 66 Sex: 42 women, 24 men Comorbidity (mean (SD) of respective measures in indicated, if available) at baseline: depression ((DASS); maximum score: 42): IG: 6.9 (7.0), CG: 5.5 (5.6); anxiety (DASS; maximum score: 42): IG: 8.1 (6.5), CG: 6.3 (6.9); stress (DASS; maximum score: 42): IG: 14.3 (8.7), CG: 12.3 (6.6); PSS (maximum score: 40): IG: 16.5 (6.5), CG: 15.0 (4.8) all participants screened for psychological distress using Kessler Psychological Distress Scale (K10): all included studies with K10 score < 30 Population description: medical students Inclusion criteria: medical students in the final 2 years of their degree course Exclusion criteria: individuals with potentially significant psychological distress in need of immediate assessment and management (K10 questionnaire score ≥ 30) Attrition (withdrawals and exclusions): 1 withdrawal in IG after trial start (withdrew before data collection and did not receive allocated intervention); lost to follow‐up: post‐intervention: 9 (IG: 7, CG: 2); 2‐month follow‐up (only in IG): 5 Reasons for missing data: no reasons specified; participants lost to follow‐up failed to respond to correspondence
Interventions	Intervention: guided mindfulness practice (brief self‐guided mindfulness of breath practice) (n = 32) delivery: audio CD; individual setting providers: self‐guided training duration of treatment period and timing: 8 weeks; 30 minutes daily practice description: guided mindfulness practice CD contains 30 minutes spoken guided mindfulness practice that participants are asked to follow independently every day during 8‐week period intervention available at www.utas.edu.au/health/students/medicine/stress-management. See website for detailed information: introduction (5 minutes) relaxation – guided relaxation with no background sounds (30 minutes) relaxation – guided relaxation with background ocean sounds (30 minutes) mindfulness – breath awareness (25 minutes) mindfulness – advanced practice of breath awareness (30 minutes) beach sounds for relaxation (30 minutes) relaxation – brief guided relaxation (5 minutes); participants asked to complete record of their practice compliance: 1 withdrawal after data collection (i.e. did not receive allocated intervention) adherence to intervention protocol: only 64% (20⁄31) completed record of practice over the 8 weeks of the intervention; participants asked to undertake intervention daily for 30 minutes over 56 days: mean number of days the intervention was undertaken by participants completing the adherence intervention record: 26.7 (range = 0 ‐ 52 days) NO REQUIREMENT of participants to continue intervention in 8‐week post‐study follow‐up period: all IG participants who completed follow‐up data also completed record of ongoing practice; 68% (13/19) reported no ongoing sessions; 6 participants who continued to use mindfulness sessions reported using intervention on a mean of 12.2/56 days (range = 3 ‐ 29 days) integrity of delivery: not specified economic information (intervention cost, changes in other costs as result of intervention): not specified theoretical basis: mindfulness‐based Control: TAU (n = 34) delivery: not specified providers: not specified duration of treatment period and timing: 8 weeks description: mindfulness intervention CD given to CG at the end of 8‐week study as incentive to remain in the study compliance: no withdrawals during treatment period integrity of delivery: not specified economic information: not specified theoretical basis: not specified
Outcomes	Outcomes collected and reported: perceived stress ‐ PSS depression ‐ DASS anxiety ‐ DASS stress ‐ DASS Time points measured and reported: 1) pre‐intervention; 2) post‐intervention (end of 8‐week intervention); and 3) 2‐month follow‐up (i.e. 2 months post‐intervention or 4 months after baseline) ONLY in IG Adverse events: no reported adverse effects of intervention
Notes	Contact with authors: We contacted the authors for the post‐intervention means and SDs for both primary and secondary outcomes in both groups with the number of participants analysed, respectively. We also asked if missing data had been imputed (Warnecke 2019 [pers comm]). Study start/end date: June 2009 (recruitment) – October 2009 Funding source: supported by a seeding grant awarded by the Australian and New Zealand Association for Health Professional Educators (ANZAHPE) Declaration of interest: none Ethical approval needed/obtained for study: approval from the University of Tasmania Human Research Ethics Committee (H0010500) Comments by study authors: not relevant Miscellaneous outcomes by the review authors: post‐intervention means and SDs for outcomes received from author Correspondence: Dr Emma Warnecke; School of Medicine, University of Tasmania; emma.warnecke@utas.edu.au; Private Bag 34, Hobart, Tasmania 7001, Australia; Tel: 00 61 3 6226 4757; Fax: 00 61 3 6226 4894
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: We carried out a multicentre, single‐blinded, randomised controlled trial" Quote: "Eligible participants were randomised centrally, using block randomisation with block sizes of two, to the intervention arm or the usual care control arm." Quote: "There were no statistically significant differences between the two arms at baseline in either demographics or baseline outcome scores." Judgement comment: insufficient information about random‐sequence generation to permit judgement of ‘Low risk’ or ‘High risk’ (method of random sequence generation is not described); verified baseline comparability of groups for sociodemographic characteristics and outcomes of interest on the basis of analysis (all Ps > 0.12)
Allocation concealment (selection bias)	Unclear risk	Judgement comment: insufficient information about allocation concealment to permit judgement of ‘Low risk’ or ‘High risk’ (i.e. method of allocation concealment during randomisation procedure is not described, only blinding of intervention specified)
Blinding of participants and personnel (performance bias) Subjective outcomes	High risk	Quote: "We conducted a multicentre, single‐blinded, randomised controlled trial (RCT) with intention‐to‐treat analysis." Quote: "Randomisation was not blinded to the individual participant because of the nature of the intervention." Quote: "Participant packs were prepared centrally. All packs contained a CD cover so that trial packs in the two arms of the study looked identical. The purpose of this was to conceal allocation." Quote: "Participants were specifically advised not to inform others about which group they were in and not to discuss the intervention. Participants were also advised not to give the intervention to anyone else." Judgement comment: single‐blind study; no blinding of participants and the outcome is likely to be influenced by lack of blinding
Blinding of outcome assessment (detection bias) Subjective outcomes	High risk	Quote: "Both the research assistant who scored and entered data and the statistician who analysed the results were blinded to group allocation." Judgement comment: insufficient information about blinding of outcome assessment; research assistants who scored and entered as well as analysed the data were blinded to group allocation; but unclear if blinded research assistant also performed the outcome assessment (i.e. distributed the questionnaires); due to performance bias (no blinding of participants), the review authors judge that the participants' responses to questionnaires may be affected by the lack of blinding (i.e. knowledge and beliefs about intervention they received)
Incomplete outcome data (attrition bias) All outcomes	High risk	Quote: "Figure 1 Progress of participants through the trial" Quote: "One participant withdrew from the trial after it began. This participant had been allocated to the intervention arm, but withdrew before any data had been collected. Baseline data (T1) were collected for all 65 remaining participants." Quote: "We conducted a multicentre, single‐blinded, randomised controlled trial (RCT) with intention‐to‐treat analysis." Quote: "Given the difference in dropout rates between the intervention and control arms, data were analysed to look for any statistical difference in those who did not complete T2 data. We found no statistically significant difference in age, sex or baseline scores for perceived stress, depression, anxiety or stress in participants who dropped out of the trial, suggesting that they left at random." Quote: "Results were analysed on an intention‐to‐treat basis. Missing data were treated as absent and were not assigned a score. No participants were excluded from the analysis." Judgement comment: reasons for missing data unlikely to be related to true outcome (imbalance in missing data between groups: IG: 1 withdrawal, 7 lost to follow‐up vs CG: 0 withdrawal, 2 lost to follow‐up; but see additional analysis with no significant difference in demographic and outcome variables between completers and non‐completers suggesting random loss); according to authors, intention‐to‐treat analysis; but missing data were treated as absent and not assigned a score; based on outcome data received from authors (24 analysed in IG, 32 analysed in CG): available‐case analysis
Selective reporting (reporting bias)	Low risk	Judgement comment: no study protocol or trial registration available but it is clear that the published reports include all expected outcomes, including those that were prespecified

α: alpha, significance level; ASQ: Attributional Style Questionnaire; BAI: Beck Anxiety Inventory; BDI‐II: Beck Depression Inventory; BPS: best possible self; Brief‐COPE: Brief Coping Orientation to Problems Experience Scale; BSN: Baccalaureate nursing students; BRS: Brief Resilience Scale; BSI: Brief Symptom Inventory; CBT: cognitive behavioural therapy; CD: compact disc; CDMSES‐SF: Career Decision‐Making Self‐Efficacy Scale ‐ Short Form; d: delta (Cohen's d, effect size); CD‐RISC: Connor‐Davidson Resilience Scale; CES‐D: Center for Epidemiology Studies Depression Scale; CFS: Coping Flexibility Scale; CG: control group; CORE‐OM: Clinical Outcomes in Routine Evaluation ‐ Outcome Measure; CPAM: Career Planning Activities Measure; CPD: career planning and development; DASS: Depression, Anxiety and Stress Scale; ERS: Emotion Regulation Scale; FFMQ: Five Facets Mindfulness Questionnaire; GAD‐7: Generalised Anxiety Disorder scale; GPA: grade point average; Grit: grit as "perseverance and passion for long‐term goals (i.e. working strenuously toward challenges, maintaining effort and interest over years despite failure, adversity, and plateaus in progress"; Duckworth 2007, p 1087‐8); GSEQ: General Self‐Efficacy Questionnaire; GSI: Global Severity Index; GSI‐R: Graduate Stress Inventory ‐ Revised; HADS‐D: Hospital Anxiety and Depression Scale ‐ German version; IG: intervention group; IRB: Institutional Review Board; ITPQ: Implicit Personality Theory Questionnaire; ITT: intention‐to‐treat analysis; JSEHPS: Jefferson Scale of Empathy ‐ Health Professions ‐ Students version; K10: Kessler Psychological Distress Scale; KIMS‐E: Kentucky Inventory of Mindfulness Skills; LOCF: last observation carried forward; LSAS‐SR: Liebowitz Social Anxiety Scale ‐ Self‐report; MASQ: Mood and Anxiety Symptom Questionnaire; MAST: Maastricht Acute Stress Test; MBI: Maslach Burnout Inventory; MBSR: Mindfulness‐Based Stress Reduction; mDES: Modified Differential Emotion Scale; MSC: Brief Mindfulness‐based Compassion; MSS: Mindfulness Skills for Students; n = sample size (e.g. in respective group), NHS: National Health Service; NURSE: Nurture nurse, Use resources, foster Resilience, Stress and Environment management; OQ‐45.2: Outcome Questionnaire; PANAS: Positive and Negative Affect Schedule; PCQ: Psychological Capital Questionnaire; PMSS‐D: Perceived Medical School Stress Scale ‐ German version; PRP: Penn Resilience Program; PSQI: Pittsburgh Sleep Quality Index; PSS: Perceived Stress Scale; PTSD: post‐traumatic stress disorder; RCI: Resilience and Coping Intervention; RCT: randomised controlled trial; RS: Resilience Scale; RSA: Resilience Scale for Adults; RSES: Rosenberg Self‐Esteem Scale; SCL90‐R: Symptom Check List ‐ Revised; SCL‐27‐plus: Symptom Checklist‐27 plus; SCS: Self‐Compassion Scale; SD: standard deviation; SPS: Social Provision Scale; STAI: State‐Trait Anxiety Inventory; SWLS: Satisfaction With Life Scale; US: unconditioned stimulus; USB: universal serial bus; UWES‐17: Utrecht Work Engagement Scale; vs: versus; WEMWS: Warwick‐Edinburgh Mental Well‐being Scale; WHOQOL: World Health Organization Quality of Life Scale; WOC: Ways of Coping Questionnaire.