Dorsomedial prefrontal rTMS for depression in borderline personality disorder: A pilot randomized crossover trial

Recently, a small literature has emerged suggesting that repetitive transcranial magnetic stimulation (rTMS) may offer benefit for MDD even in BPD patients, perhaps by enhancing cognitive control, and/or disrupting excessive 'non-reward' activity in right orbitofrontal regions. This study aimed primarily to assess the therapeutic effects of dorsomedial prefrontal cortex (DMPFC)-rTMS against MDD symptoms in BPD patients, and secondarily to assess whether the therapeutic effects ensued via mechanisms of reduced impulsivity and core BPD pathology on clinical scales (BIS-11, ZAN-BPD) or of reduced alpha- and theta-band activity on EEG recordings of right orbitofrontal cortex..

In a crossover-design trial, 20 BPD patients with MDD underwent 2 × 30 session/15 day blocks of either active-then-sham or sham-then-active bilateral 20 Hz DMPFC-rTMS.

Sixteen out of 20 patients completed treatment. A significant (p = 0.00764) crossover effect was detected, with overall reductions in HamD17 score from 23.1±SD3.1 to 10.75±SD5.8. Nine out of 16 (56.3%) treatment completers achieved response (>50% improvement) and 6/16 (37.5%) achieved remission (HamD≤7), maintained at 1 month followup. BIS-11 scores remained unchanged, and ZAN-BPD scores improved similarly in both groups with no significant crossover effect. Change in low-band power over right orbitofrontal regions correlated with clinical improvement.

This was a crossover study with a small sample size. A randomized controlled trial with larger sample size will be needed to establish the efficacy more definitively.

The results suggest efficacy for DMPFC-rTMS in treating MDD in BPD, and provide a foundation for a larger future trial.