“…There are several psychotherapeutic approaches specifically developed for adolescent with BPD: e.g., dialectical behavior therapy for adolescents (DBT-A; Fleischhaker et al, 2011 ), mentalization-based treatment for adolescents (MBT-A; Rossouw and Fonagy, 2012 ), adolescent identity treatment (AIT; Foelsch et al, 2014 ), and schema-focused psychotherapy for adolescents ( Loose, 2015 ). The therapeutic process with BPD patients is often challenging because symptoms of BPD (e.g., rejection sensitivity) can hinder the construction of a good therapeutic relationship ( McMain et al, 2015 ) through an increased risk of ruptures of the therapeutic alliance ( Schenk et al, 2019 , 2020 ). Psychotherapy process research investigates active ingredients of therapeutic interventions and helps improve therapeutic approaches, as well as informing psychotherapists about the mechanisms of change and how they may leverage these actions ( Hardy and Llewelyn, 2015 ; Zimmermann et al, 2018 ).…”