Feasibility and Acceptability of the Unified Protocol for Burnout

Feasibility will be assessed in terms of recruitment capability, practicality, adaptability, and implementation fidelity. Recruitment capability refers to the number of participants successfully identified and enrolled. Practicality concerns whether the intervention can be delivered using available resources, time, training, and materials. Adaptability refers to the flexibility of the intervention procedures to accommodate diverse needs. Implementation fidelity refers to the extent to which professionals are able to deliver the intervention as intended.

Therapist adherence will be evaluated using the Therapist Adherence Rating Scale for the Unified Protocol (TARS-UP), adapted for use with the Unified Protocol for Burnout. Each intervention module will be evaluated by an observer using a checklist that captures the presence or absence of core treatment components and provides global ratings of therapist performance (e.g., rapport, engagement, session management, and overall session quality).

A questionnaire assessing participants' module-specific acceptability will be administered following each intervention module. The questionnaire includes five Likert-type items (two assessing group process and three assessing module content) and two open-ended questions designed to capture qualitative feedback.

A brief module-specific acceptability questionnaire developed for this study will be administered to psychotherapists following delivery of each intervention module. The questionnaire consists of structured yes/no and yes/somewhat/no questions assessing implementation issues (e.g., barriers to delivery and adequacy of session time), numeric rating questions (1-10) assessing perceived fit of the module content and participant engagement, and open-ended questions allowing therapists to elaborate on their responses and provide feedback on strengths of the module and areas for improvement.

An 8-item questionnaire developed by Sekhon et al. (2022) will be used to assess acceptability of the intervention from both participant and psychotherapist perspectives. The questionnaire is based on the Theoretical Framework of Acceptability (TFA). Items corresponding to each TFA construct will be analysed separately. No composite total score will be calculated. Overall acceptability will be assessed using the single general acceptability item.

Attrition will be operationalized in terms of drop-out rates. Adherence will be operationalized as the number of sessions attended and the quality of completed homework assignments.

Burnout will be assessed using the Burnout Assessment Tool-23 (BAT-23; Schaufeli et al., 2020), a 23-item self-report measure rated on a 5-point Likert-type scale. The BAT-23 assesses core burnout symptoms, which can be analysed separately or as a composite score, as well as secondary distress symptoms, which are summed and interpreted as a single score.

To assess depression severity, the Overall Depression Severity and Impairment Scale (ODSIS-5; Bentley et al., 2014) will be used. The ODSIS-5 is a 5-item Likert-type scale, with total scores ranging from 0 to 20. Higher scores indicate greater depression severity.

To assess anxiety severity, the Overall Anxiety Severity and Impairment Scale (OASIS-5; Norman et al., 2006) will be used. The OASIS-5 is a 5-item Likert-type scale, with total scores ranging from 0 to 20. Higher scores indicate greater anxiety severity.

Well-being will be assessed using the The World Health Organization-Five Well-Being Index (WHO-5), a 5-item self-report measure rated on a 6-point Likert-type scale (World Health Organization, Regional Office for Europe, 1998). Total scores range from 0 to 25, with higher scores indicating greater well-being.

Emotional regulation will be assessed using the Difficulties in Emotional Regulation scale -16 (DERS-16; Bjureberg et al., 2016), an 16-item self-report measure rated on a 5-point Likert scale. Item responses will be summed to yield a total score ranging from 16 to 80, with higher scores indicating greater difficulties in emotion regulation.

Group therapeutic processes will be assessed using the Therapeutic Factors Inventory-8 (TFI-8; Tasca et al., 2014), an 8-item self-report measure rated on a 7-point Likert scale. Item responses will be summed to yield a total score ranging from 8 to 56, with higher scores indicating stronger perceived group therapeutic factors.