OBrien 2019.

Study characteristics
Methods	Study design: randomised controlled trial Study grouping: parallel group
Participants	Baseline characteristics Acceptance and Commitment Therapy Age in years (mean ± SD): NR Sex (N (% female)): NR Sample size: 37 Years of experience (mean ± SD): NR Control (wait list) Age in years (mean ± SD): NR Sex (N (% female)): NR Sample size: 34 Years of experience (mean ± SD): NR Overall Age in years (mean ± SD): 37.91 ± 13.24 Sex (N (% female)): 61 (86%) Sample size: 71 Years of experience (mean ± SD): 11.97 ± 9.86 Included criteria: NR Excluded criteria: NR Pretreatment: there were also no significant between‐group differences on any demographic measure at baseline or follow‐up (all P‐values > 0.20) Compliance rate: 87% Response rate: NR Type of healthcare worker: Nurses and nurse aides
Interventions	Intervention characteristics Acceptance and Commitment Therapy Type of the intervention: Intervention type 4 ‐ Combination of two or more of the above Description of the intervention: The intervention topics included acceptance, mindfulness, psychological flexibility, willingness to experience discomfort, present‐moment focus, self‐as‐context, values identification, and values‐congruent committed action. The number of sessions: 2 Duration of each session on average: 2.5 h Duration of the entire intervention: 1 week Duration of the entire intervention short vs long: short Intervention deliverer: Faculty and trained graduate students pro‐vided the ACT intervention. All graduate student therapists completed a semester‐long seminar in the research, theory, and application of mindfulness and ACT therapies. Experiential training was also provided to the therapists in the Bowling Green State University psychology clinic. Intervention form: at participant work sites, the average group size per session was three with a maximum of seven per group. Control (wait list) 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	General Health Questionnaire (GHQ‐12) Outcome type: ContinuousOutcome
Identification	Sponsorship source: This project was supported by a research grant provided by the Ohio Bureau Workers Compensation Ohio Occupational Safety and Health Research Program. Country: United States Setting: Nursing homes and assisted living facilities Comments: NR Authors name: William H. O’Brien Institution: Department of Psychology, Bowling Green State University Email: wobrien@bgsu.edu Address: Bowling Green, OH 43403 Time period: NR
Notes	GHQ included in analysis 4.1
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Interested participants were randomly assigned to the treatment or control group and then contacted by the project coordinators. An assessment session was then scheduled. Randomisation sequence generation process not described
Allocation concealment (selection bias)	Unclear risk	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	Quote: "participants were informed that they were either in the treatment group or wait‐list control group."
Blinding of outcome assessment (detection bias) All outcomes	High risk	Quote: "This was described to them as the immediate treatment group or the delayed treatment group." Participants were not blinded whereas outcomes are self‐reported.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "There were no significant differences in dropout rates between the ACT and control groups (Fisher’s exact test p = 0.36)."
Selective reporting (reporting bias)	Unclear risk	No trial registration, nor did we find one online.
Other bias	Unclear risk	Response rate was not reported.