Kharatzadeh 2020.

Study characteristics
Methods	Study design: randomised controlled trial Study grouping: parallel group
Participants	Baseline characteristics Emotion regulation training Age (mean ± SD): NR Sex (N (% female)): NR Sample size: 30 Years of experience (mean ± SD): NR Control (no intervention) Age (mean ± SD): NR Sex (N (% female)): NR Sample size: 30 Years of experience (mean ± SD): NR Overall Age (mean ± SD): NR Sex (N (% female)): NR Sample size: 60 Years of experience (mean ± SD): NR Included criteria: employment in intensive or critical care units, no previous participation in an ERT program and not currently taking psychotropic medication or other unprescribed substances. Excluded criteria: NR Pretreatment: at baseline, an independent sample t‐test showed no significant difference between the two groups in terms of age and working hours per month. The two groups also did not differ in sex, nor marital status. There were no between‐group differences in CERQ, DASS‐21, and ProQoL‐5 subscale scores at baseline. The statistical analysis controlled for baseline scores for CERQ, DASS‐21 and ProQoL‐5 scores as confounders. Compliance rate: four of the 30 (13%) participants randomised to the intervention group missed more than 2 sessions Response rate: nine of the 71 (13%) eligible participants did not want to participate Type of healthcare worker: nurses
Interventions	Intervention characteristics Emotion regulation training Type of the intervention: Intervention type 1 ‐ to focus one’s attention on the experience of stress Description of the intervention: The ERT program was based on Gross'(1998) emotion regulation model, which identifies five points in the emotion generative process. The five points are situation selection, situation modification, attentional deployment, cognitive change,and response modification The number of sessions: six sessions Duration of each session on average: 2 hours Duration of the entire intervention: NR Duration of the entire intervention short vs long: short Intervention deliverer: Clinical psychologist Intervention form: NR Control (no intervention) Type of the intervention: NA Description of the intervention: NA The number of sessions: NA Duration of each session on average: NA Duration of the entire intervention: NA Duration of the entire intervention short vs long: NA Intervention deliverer: NA Intervention form: NA
Outcomes	Professional Quality of Life (ProQol) ‐ Burn out Outcome type: ContinuousOutcome DASS ‐ depression Outcome type: ContinuousOutcome DASS ‐ Anxiety Outcome type: ContinuousOutcome DASS‐ Stress Outcome type: ContinuousOutcome
Identification	Sponsorship source: NR Country: Iran Setting: Hospital Comments: NR Authors name: Hamid Kharatzadeh BSc, MSc, PhD Candidate Institution: Department of Clinical Psychology, Faculty ofHuman Sciences, Shahed University, Tehran, Iran Email: m_alavi@nm.mui.ac.ir Address: Mousa Alavi, Nursing and Midwifery CareResearch Center, Faculty of Nursing andMidwifery, Isfahan University of MedicalSciences, Isfahan, Iran Time period: 2018‐2019
Notes	DASS‐stress included in analysis 1.1 DASS ‐ depression included in analysis 1.4
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "randomly allocated to either the treatment group" Using a computer‐based randomization allocation
Allocation concealment (selection bias)	Unclear risk	Quote: "using a computer‐based randomiza‐ tion allocation (refer to the study CONSORT diagram, Figure 1)." Insufficient information to understand whether intervention allocations could have been foreseen in advance of, during, enrolment.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants were not blinded.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Participants were not blinded whereas outcomes are self‐reported.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Follow‐up lost less then 20% (53 of the 60 randomised participants included in the analysis).
Selective reporting (reporting bias)	Low risk	IRCT20171005036572N3. No indication of selective outcome reporting
Other bias	Low risk	No indication of other sources of bias