Data collection
Altogether, ten patients from the intervention group of the main trial were invited to the semi-structured interviews via telephone. Two of these invited patients had to be excluded, because of compliance issues (We conducted semi-structured individual interviews with patients to obtain in-depth information about their perception concerning the role of the GP teams in provision of the combined brief NET with case management. Furthermore, we asked for patient’s perspective on effectiveness of the NET.All interviews were conducted via telephone from the interviewer`s home office and audiotaped. No one else was present during these interviews besides the participants and researchers. All participating patients already had received the three scheduled NET sessions according to the study protocol of the main trial [The interview guideline (e-supplement In detail, we focused on.The aspects of the course and implementation of the NET in primary care are theoretically described in the therapy manual [The overall acceptance of the NET intervention. In therapy research, the subjective retrospective assessment of patients is considered to be of great prognostic importance for long-lasting effectiveness within a contextualized environment like the GP setting [The interview guideline was discussed in the PICTURE team at both study centres and in qualitative research circles (“Berlin method meeting for qualitative research”). The resulting findings were incorporated.