¹Medical Faculty of Masaryk University and University Hospital Brno, Department of Psychiatry, Brno, Czech Republic, ²Medical Faculty of Masaryk University, Department of Psychiatry, Brno, Czech Republic

Background: Borderline personality disorder (BPD) is a devastating pervasive mental disorder characterized by emotion regulation impairment and marked impulsive behavior, including self-harming and suicidal behavior. Among other treatment possibilities in BPD, repetitive transcranial magnetic stimulation (rTMS) has been repeatedly used with inconclusive results because of protocols heterogeneity, lack of randomized controlled trials and poor quality of included studies, including high risk of methodological biases (Lisoni et al., 2022; Mansour et al., 2025).

Aims & Objectives: The aim of the project was to assess the efficacy and safety of high frequency rTMS of the right dorsolateral prefrontal cortex compared with sham stimulation in female patients with borderline personality disorder.

Method: The study was organized as a double blind and sham stimulation-controlled study. Female patients were randomized to one of the study arm – either active rTMS or sham stimulation. Patients underwent 15 daily stimulation sessions during a period of three weeks. Gradual titration of the individual resting motor threshold (rMT) was applied (from 90% to the final intensity of 120% rMT). Patients received 2,000 pulses during one session with 10 Hz frequency. Sham TMS was performed by sham coil. Primary outcome was the decrease of borderline symptoms measured by Borderline Symptoms List-23 (BSL-23). Secondary outcomes included depressive symptoms measured by Beck Depression Inventory II (BDI-II), symptoms of anxiety measured by Beck Anxiety Inventory (BAI), and the increase of emotional regulation measured by Difficulties in emotion regulation scale (DERS).

Results: 40 patients were randomized, 30 patients underwent at least one stimulation (15 in active arm, 15 in sham arm) and were included in the study, 29 completed the stimulation. We did not find significant difference between active stimulation and sham stimulation in BSL-23 (primary outcome), symptoms of anxiety in BAI, and the increase of emotional regulation in DERS. We found significant improvement in depressive symptoms measured by BDI-II after active stimulation compared to sham stimulation.

Discussion & Conclusions: We did not find significant difference between active stimulation and sham stimulation in symtoms of borderline personality disorder. These results are similar to the results of German researchers who used rTMS as augmentation of dialectical behavioral therapy (Kujovic et al., 2024). But we found significant improvement of depressive symptoms in our patients after active rTMS compared to sham stimulation which is similar to the results of other German researchers who described positive results of rTMS in patients with comorbid BPD and depression (Reinsberg et al., 2023). The stimulation of our patients was safe without serious side-effects. Only one patient finished the stimulation prematurely because of headache and lack of time to come everyday.
We can conclude that although our primary outcome was not met - there was no statistically significant reduction in BSL-23 scores in patients after active rTMS compared to sham, rTMS appears to be a promising therapeutic method for at least some symptoms (specifically depressive symptoms) in patients with BPD. Its safety profile and tolerability is good. But its efficacy must be verified in larger randomized controlled trials.