Background: Mentalization-Based Therapy (MBT) was originally developed as a structured psychotherapy approach developed to treat borderline personality disorder (BPD) lasting up to 18 months in outpatient settings. However, a short-term (5 months) MBT program has recently been developed. No studies have investigated how MBT therapists experience the shift towards conducting short-term MBT for BPD.

Objective: The objective of this study was to explore therapist experiences with conducting short-term MBT for outpatients with BPD in the Danish mental health services.

Methods: Semi-structured qualitative interviews were conducted with seven therapists about their experiences with short-term MBT after a one-year pilot phase. The interviews were verbatim transcribed and analyzed using thematic analysis.

Results: The following four major themes from the therapists’ experiences with short-term MBT were found in the qualitative analysis: (1) The longer the better, (2) Change processes can be intellectual or experiential, (3) Short-term therapy is hard work, and (4) Termination is more challenging in short-term MBT.

Conclusion: Most therapists were overall reluctant towards changing from long-term to short-term MBT. These therapist experiences could inform implementation of short-term MBT in mental health settings in the future.