Ventrolateral prefrontal-amygdala repetitive transcranial magnetic stimulation (rTMS) modulation of impulsivity in borderline personality disorder: a proof-of-concept study

Impulsivity and emotional dysregulation are core symptoms of Borderline Personality Disorder (BPD) for which therapeutic options are very limited. Prior neuroimaging studies suggest that BPD symptoms may be related to fronto-amygdala circuit dysfunction. This proof-of-concept study examined whether individualized ventrolateral prefrontal cortex (VLPFC)-amygdala circuit modulation with Repetitive Transcranial Magnetic Stimulation (rTMS) could alter impulsivity and emotional dysregulation in BPD. Eleven participants with BPD underwent resting-state functional Magnetic Resonance Imaging (rsfMRI) scans to identify individualized right and left VLPFC targets with the strongest functional connectivity to the ipsilateral amygdala. They then performed delayed discounting and emotional reactivity to social exclusion tasks to assess impulsivity and emotional reactivity, respectively, followed by a single session of intermittent Theta Burst Stimulation (iTBS) administered to left and/or right VLPFC targets. Tasks were repeated after stimulation to assess change in impulsivity and reactivity. Mixed-model linear regression analysis showed that right VLPFC, but not the left or bilateral VLPFC stimulation, was associated with a significant reduction of impulsivity (χ2(2) = 7.76, p = 0.02) but not emotional reactivity. No subjects experienced significant adverse events. These results suggest that the right VLPFC iTBS is a safe, tolerable, and promising procedure for modulating impulsivity in BPD.