People living with borderline personality disorder (BPD) may also experience depression, anxiety or both. A review by Francis, Fino and Heym examined whether three therapies—dialectical behaviour therapy (DBT), mentalisation-based treatment (MBT) and internal family systems (IFS) therapy—show benefits when these difficulties occur together.
The review found promising signals for DBT and MBT, but it did not establish that one treatment is best, or that the findings apply equally to everyone. IFS was not tested in any of the included studies.
Why the overlap matters
BPD is described as involving an unstable sense of self, difficulty managing intense emotions and challenges in maintaining healthy relationships. The source states that up to 70% of people diagnosed with BPD are also diagnosed with depression, while up to 90% have an anxiety disorder.
Depression alongside BPD is associated with a higher risk of relapse and suicide attempts. Anxiety has been linked with more severe BPD symptoms. In England, 1.9% of adults screened positive for BPD in the 2023–24 Adult Psychiatric Morbidity Survey.
What the therapies aim to do
- DBT teaches practical skills for managing intense emotions, tolerating distress and improving relationships.
- MBT focuses on understanding a person’s own thoughts and feelings, as well as the thoughts and feelings of other people.
- IFS views the mind as containing different “parts” and aims to help those parts work together when trauma has disrupted their balance.
What the review included
The researchers followed PRISMA guidelines and searched five databases. Eligible studies included people aged 12 or older with BPD and co-existing depression or anxiety confirmed through a diagnostic manual or clinical interview. Participants could meet full criteria for BPD or fall below the diagnostic threshold.
Of 518 identified studies, 12 were included: four randomised controlled trials and eight naturalistic studies. Ten examined DBT, two examined MBT and none examined IFS. Nine studies were rated good quality, one excellent and two fair using the Downs and Black checklist.
The studies were too different in their participants, outcome measures, treatment formats and intervention lengths to be combined statistically. The researchers therefore synthesised the findings narratively rather than producing a single overall effect estimate.
What the findings suggest
Several DBT studies reported reductions in BPD symptoms, depression and anxiety, although the results were not consistent across every study. One study found significant reductions in depression and anxiety while a waiting-list group showed no change. DBT was also associated with improved coping and reduced emotion suppression in the reported studies.
In one inpatient DBT study, 62% of participants abstained from self-harm, compared with 31% in a waiting-list group. However, another DBT study found no significant change in self-harm. Two DBT studies also reported reductions in emergency department visits, inpatient admissions or length of stay.
The two MBT studies reported reductions in BPD and depressive symptoms, but neither assessed anxiety. MBT was associated with improved relational functioning and relationship satisfaction.
One naturalistic MBT study followed participants for 18 months. The proportion reporting at least one suicide attempt fell from 31.7% before treatment to 0% at 12 months, then rose slightly to 3% by the end of the study. The proportion experiencing inpatient admission fell from 35.6% before treatment to 3% after treatment.
Why caution is still needed
The authors described the evidence as limited and heterogeneous. Many studies had small samples, limited follow-up or no comparison group. In most studies, only part of the sample had co-existing depression or anxiety, making it difficult to know whether the results specifically apply to people with these combinations.
None of the included studies reported whether therapists followed DBT or MBT treatment manuals. The review was also limited to English-language publications and did not report a grey-literature search, which may increase the risk of language or publication bias.
Shorter DBT programmes, including eight-week interventions, showed benefits in some included studies. The evidence does not show, however, that brief DBT is equivalent to full-length DBT. Effects also varied by symptom: anger, fear and shame improved among participants with co-existing anxiety but not among those with co-existing depression.
Overall, the review supports further research into DBT and MBT for BPD alongside depression or anxiety. It also highlights a clear evidence gap: the effectiveness of IFS for this population remains untested in the studies included in the review.
AI tools were used to assist with the preparation of this article.
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