Feasibility
HOLIDAY, ATTRITION
Time needed to recruit the participants: The time needed to recruit at least 40 eligible participants in the study was six months (January-June 2021) (Table Program preference and expectations: Out of 62 individuals that were screened for eligibility during the first contact, most (58.1%) preferred to participate in the wilderness program (Table Willingness to be randomized: Although all 62 individuals agreed to be randomized at the first contact, it turned out that one individual who had a strong preference for the holiday program dropped out of the study because she had been allocated to the wilderness program. Another participant who ended up in the holiday program confessed that if she had been randomized to the wilderness program, she would have dropped out. Willingness to be randomized was thus 60 out of 62 individuals (96.8%) (Table Attrition rate: Out of the 59 individuals initially enrolled, a total of 17 dropped out after randomization but before start of the intervention. The attrition rate before the start of the intervention was thus 28.8% in total, 34.5% (10/29) in the wilderness and 23.3% (7/30) in the holiday program. Since no participant dropped out of the study after entering the intervention, neither in the wilderness program nor in the holiday program, the attrition rate after start of the intervention was 0% overall and, in both programs (Table Adherence to the study program: The adherence to program-related activities was 91.7% in the wilderness program, and 97.8% in the holiday program (Table Data collection completeness: There were few missing data in both arms. Overall, 96.7% of all questionnaires were completed by participants in the wilderness program and 99.5% of all questionnaires by participants in the holiday program (Table 