Combining Transcranial Magnetic Stimulation With Emotion Regulation Skills Training in Borderline Personality Disorder

Emotion dysregulation has long been established as the core characteristic feature of borderline personality disorder (BPD). Large scale mediation analyses have identified emotion dysregulation as a key driver of the most impairing effects of this disorder, including interpersonal difficulties, self-harm and suicidality.1 Further, emotion dysregulation has been found to have a transactional relationship with overall BPD symptoms, with significant bi-directional relationships between severity of emotion regulation difficulties and severity of BPD symptoms, suggesting emotion dysregulation goes hand in hand with BPD. Thus, effectively improving emotion regulation (ER) skills is crucial to ameliorating the devastating experience and deleterious effects of this disorder.

For the past decade, we have been studying emotion regulation both on the behavioral level and on the level of neurocircuit function. These studies have primarily focused on bipolar disorder (BD) rather than BPD. However, there is significant overlap in the experience and negative effects of emotion dysregulation between the two disorders, and they are often diagnostically indistinguishable. The specific focus on emotion dysregulation rather than symptoms means these studies are likely relevant to both disorders. This is supported by findings in the BPD literature that overlap with our prior studies. Key takeaways from these studies thus far are: 1) Response to behavior-based ER skills training alone (e.g. CBT) is limited by impaired baseline functioning of ER neurocircuitry, with weaker functional connectivity predicting poorer outcomes. Similar findings have been shown in BPD, with weaker baseline functioning of ER neurocircuit regions predicting poorer outcomes to DBT specifically and psychotherapy in general. 2) Functional connectivity deficits between key nodes in ER neurocircuitry (anterior insula, inferior parietal lobule) distinguish BD from healthy controls, and is significantly related to severity of emotion dysregulation. Similar findings have been shown in studies of BPD patients, which found similar weak functional connectivity between anterior insula and ER circuit regions including the IPL, significantly associated with ER deficits. 3) Modulation of this ER circuit pathway using transcranial magnetic stimulation (TMS) improves ER functional connectivity and behavioral performance on a laboratory task. We have been able to demonstrate both increased AI-IPL functional connectivity and improved performance on an ER behavioral task following IPL stimulation in patients with BD. Given the existing overlap in findings related to ER in both disorders, we hypothesize similar results to be found in patients with BPD.

Thus, taken together, behavioral ER skills training may be a viable approach to improving emotion dysregulation, but is limited by intrinsic ER neurocircuit function. Directly modulating ER neurocircuitry improves ER neurocircuit function and performance on a laboratory analogue of ER behavior, but the effects on real-world ER skills is unknown. Importantly, focusing on ER related neurocircuit function in isolation from the behavioral and psychological processes involved in ER, and vice versa, may not be sufficient to provide relief to those individuals struggling with severe emotion dysregulation, as there is an important bidirectional relationship between these neurocircuit and behavioral components. It remains an open question, therefore, whether improving neurocircuit function supporting emotion regulation while simultaneously addressing the psychological and behavioral processes driving emotion dysregulation can provide synergistic relief to the devastating impact of emotion dysregulation.

Existing approaches to improving ER in BPD Dialectical Behavioral Therapy (DBT) has long been the gold standard for treating individuals with BPD. However, whereas DBT can be a powerful and effective intervention, outcomes are hampered by the extensive length of treatment (one year for a full course of DBT), leading to treatment dropout rates as high as 58% in outpatient settings. This has led to the development of brief versions of DBT (e.g. 12 sessions, 6-month protocols) focused on teaching mindfulness and emotion regulation skills. However, response to these briefer versions have been discouraging, with over 50% of patients showing no clinically significant decrease in symptoms, and sometimes further deterioration. Further, evidence suggests individuals with BPD who show greater baseline deficits in emotion regulation neurocircuit function benefit less from treatment. This suggests two great needs for the field of BPD treatment: 1) briefer efficacious behavioral protocols focused on emotion regulation skills training, and 2) interventions that can strengthen ER neurocircuit function.

The current proposal seeks to address both of these needs, by collecting early Phase 1 pilot data on a combined approach using neuromodulation to strengthen ER neurocircuitry combined with an intensive, brief behavioral approach to teaching ER skills. If we can show this approach is feasible and acceptable, and preliminary evidence for efficacy, data from this trial will provide crucial preliminary evidence to support funding for a larger, randomized controlled clinical trial