Overview

Borderline personality disorder (BPD) is a life-threatening, costly public health crisis affecting \~1-3% of North Americans, with 10% dying by suicide and annual healthcare costs of \~$63k (Canadian Dollars)/patient. Further, people with BPD's intimate relationships are highly disrupted, and their partners report elevated mental health problems but little access to treatment. Existing BPD treatments are resource-heavy, inaccessible, and 47% of people with BPD do not respond to them. These treatments also neglect relationship problems and intimate partner's mental health concerns, even though they are thought to play a key role in BPD maintenance. BPD interventions may produce stronger, quicker, and more durable outcomes if they incorporated partners to target both the emotional and relationship core of BPD. Moreover, incorporating partners into interventions may improve relationship outcomes and partner mental health without added resource investments.

Accordingly, members of our team developed Sage. Named after a plant that thrives in relationship with its ecosystem, Sage is a brief, 12-session conjoint intervention for people with BPD and their intimate partners that targets BPD, relationship conflict, and partner mental health. Our recent uncontrolled trial provides preliminary support for its efficacy.

As a next step in testing Sage, it is critical to utilize a Randomized Controlled Trial (RCT) design to identify if Sage is more efficacious than standard care that these couples typically receive; supportive individual psychotherapy (SIP) for people with BPD and their partners. The investigators propose to conduct the first RCT of Sage for couples wherein one member has BPD. The study will examine if Sage is more efficacious than SIP in improving BPD symptoms (primary outcome), as well as relationship conflict and partner mental health (secondary outcomes), as well as a range of other outcomes, from pre- to post-intervention, and post-intervention to follow-up. It will also investigate factors that influence treatment response, BPD severity, and related problems.

Up to 152 couples wherein one member has BPD will be randomized to receive Sage or SIP. Gold-standard measures of primary, secondary, and exploratory outcomes will be administered at baseline, mid-intervention, post-intervention, and a one-month, three- month, and six-month follow-up.

Eligibility

INCLUSION CRITERIA

1. Participant with borderline personality disorder (BPD) meets full diagnostic criteria for BPD (i.e., five or more BPD diagnostic criteria per the Diagnostic and Statistical Manual of Mental Disorders-5-TR)
2. Both members are at least 19-years-old
3. Both members consent to study participation
4. Both members consent to a member of the research team contacting one of their provided emergency contacts if there are imminent safety concerns.
5. Both members consent to having assessment interviews and treatment sessions audio- and video-recorded
6. Both members members reside in Ontario (with no plan to leave the province during the course of the study)
7. Both members members are fluent in English
8. Both members are willing to receive emails about the study
9. Both members have regular internet access from a private location for completion of study appointments

   EXCLUSION

10. Severe intimate partner violence in their relationship in the past year (Endorsement of severe intimate partner violence items on Conflict Tactics Scale-2)
11. DSM-5 criteria A and B of schizophrenia, not better accounted for by BPD
12. Hospitalization in the past year for mania, or mania in the past three months
13. A substance/alcohol use disorder that is likely to require medical intervention (e.g., detoxification) to reduce use
14. A medical condition that is likely to require hospitalization within the next year
15. Scaled score below 70 on the Test of Premorbid Functioning, suggesting impaired intelligence and/or probable traumatic brain injury
16. Either participant in the dyad is not able to show proof of identification upon request at any point throughout the study or is not able to provide an accurate phone number or address upon request.
17. The individual with BPD is currently receiving an empirically-supported BPD treatment and is unwilling to pause the therapy for the duration of the active treatment phase