Ethics approval and consent to participate
All participants provided written informed consent before participating. The study complied with the Declaration of Helsinki and was reviewed and approved by the Ethics Committee of the Canton Bern, Switzerland (ID: 2018–00230).In Switzerland, young people even under the age of 14 have the right of non-information of their legal guardians with respect to a participation in a psychotherapeutic treatment. The capacity to judge is deemed to exist from around the age of 14. Therefore, young people under the age of 16 have the right to receive therapeutic services without the consent of their legal representatives (Swiss Civil Code: Art. 305 Abs. 1 and Art. 19c ZGB; Federal Constitution of the Swiss Confederation: Art. 11 Abs. 2 BV). In accordance with Swiss law, we therefore examined at the end of the information session, whether youth did fully understand the study procedure and their rights. If this was approved, we did no longer have the right to inform the parents, unless the person was either suicidal or a threat to others (Swiss Criminal Code: Art. 321 StGB). Based on this right, we forewent not to obtain parental consent and adolescents under the age of 18 years were not obliged to inform legal guardians about their participation. However, adolescents were motivated to inform their parents/ legal representatives about the study and a legal representative study information was provided if adolescents agreed to inform their representatives. Therefore, informed consents were signed either by participating youth alone or together with their legal guardians.This procedure has been submitted and approved by the cantonal ethics committee. The Journal examined and approved the legal basis of this procedure as well (Munsch et al. 2021).