The objective of this project is to investigate factors that contribute to the success and lack of success in DBT among individuals with BPD and a history of self-harm in a clinical psychiatric setting.

1. Do certain personality factors and identity disturbance predict the treatment outcome of DBT in individuals with BPD?
2. Do changes in identity disturbance, self-hate, or emotion regulation mediate the treatment outcome of DBT in individuals with BPD?
3. Do specific personality profiles moderate the treatment outcomes of DBT for individuals with BPD?
4. When does the primary treatment effect occur, and does this effect persist after a 12-month follow-up period?

Borderline Personality Disorder (BPD) is a complex and enduring mental health condition characterized by a range of symptoms. The consequences of BPD are severe, causing individual suffering, impairments in daily functioning, and increased mortality rates. Dialectical behavior therapy (DBT) is one of the most widely used treatment models for BPD and self-harm. DBT has demonstrated positive outcomes but not all individuals benefit equally from this therapy, highlighting the need for further exploration. Specifically, there is a knowledge gap regarding what predicts positive treatment response. Research exploring this topic, has highlighted the potential significance of emotion regulation, personality profiles, self-concept, and identity disturbance in understanding the outcomes of individuals with BPD.

The primary objective of this research project is to investigate the factors that contribute to the success and lack of success in DBT.

All individuals referred to DBT-treatment in the Adult psychiatric clinic in Lund will be offered participation in the study. All study participants receive the same treatment as those who chose not to participate. Measures will commence after treatment contracts have been negotiated and the treatment will continue up to a maximum treatment length of one year.

Data will be retrieved from databases, medical records as well as collected as self-report forms. Self-report measures will be conducted every three months, at end of treatment and at follow up 12 months after end of treatment. Data from registries and charts will be collected at time of consent and at follow up 12 months after treatment.

Inclusion Criteria:

• Borderline personality disorder as defined by the DSM-V (assessed with SCID or uquivalent).
• Self-harm over the past 12 months
• Offered DBT at the Lund adult psychiatric clinic

Exclusion Criteria:

• Unable to read or communicate in Swedish

Adults with Borderline personality disorder in a specialized psychiatric setting. A majority of the individuals will have comorbid psychiatric conditions and have been offered other pharmacological and psychological treatments through their GP or a general psychiatric outpatient unit prior to the study intervention. Other treatments are permitted for inclusion in this study.

Possibly not aoolicable due to Swedish data protection law