Borderline personality traits do not influence response to TMS.

Comorbid personality disorders are common in patients with major depressive disorder (MDD). Individuals with comorbid borderline personality disorder (BPD) may be less responsive to electroconvulsive therapy (ECT), but it remains unclear whether BPD affects responsiveness to transcranial magnetic stimulation (TMS). We sought to investigate the association between BPD and response to TMS. We conducted a retrospective analysis of individuals receiving TMS (n=356) at McLean Hospital. We also included individuals receiving ECT (n=1434) as a control. All individuals completed the McLean Screening Instrument for BPD (MSI-BPD) at baseline. Response to treatment was measured by the Quick Inventory of Depression Symptomatology Self-Report (QIDS-SR). We performed general linear models (GLMs) to assess the effect of BPD on treatment response to TMS and ECT. At baseline, the ECT group had a higher average QIDS-SR score (21.4 vs. 20.3, p<0.05). For both treatment groups, the number of treatments had a significant effect on depression severity. For the TMS group, there was no significant Group x Time interaction on QIDS-SR score (p=0.18). However, for individuals receiving ECT, there was a significant Group x Time interaction on QIDS-SR score (p=0.02), suggesting that BPD significantly impaired response. These results suggest that borderline personality traits did not affect treatment response to TMS for MDD. BPD traits modestly predicted response to ECT, which is consistent with the literature. These results require replication in a clinical trial.