Descriptive data
First, selection effects were investigated, to identify whether the sample of participating (n = 356) and non-participating patients (n = 147) differed. Corresponding statistics are listed in Table 
Description of the sample and determination of the differences between the subgroups non-participants and participants as well as groups A and B. Statistical differences (determined by F-test or chi-square test) are marked with asterisksYears of education (school + vocational)[m (sd)]
The amount of missing data in the burden data varied greatly from item to item: n