Bilateral rTMS Shows No Advantage in Depression nor in Comorbid Depression and Anxiety: A Large Naturalistic Study

Abstract

Background: The objective was to determine if adding low-frequency (LF) right-sided rTMS treatment to the standard high-frequency (HF) left-sided treatment, together referred to as bilateral treatment, confers any additional benefit for depressive or anxiety outcomes. Design/Methods: A retrospective chart review of patients treated with rTMS was conducted, from January 2015 through December 2018, yielding 361 patients. All patients were treated with a figure-of-8 coil for a major depressive episode, and their protocol was either HF left-sided treatment or bilateral treatment. The Generalized Anxiety Disorder 7-item scale (GAD-7) was the anxiety outcome measure, and the Patient Health Questionnaire (PHQ-9) was the depression outcome measure. Results: There was no significant difference in GAD-7 change scores between patients who had unilateral (GAD change=4.2) versus bilateral rTMS (GAD change=4.5). Unilateral rTMS patients had greater improvement in PHQ-9 than bilateral (7.2 vs. 5.0; P=.011). Patients switching from unilateral to bilateral treatment mid-course had overall poorer outcomes than patients who did not. Conclusions: This large, naturalistic study shows no advantage for bilateral treatment in any group or condition examined, and for depression outcomes, there may be a deficit with bilateral versus unilateral treatment. The results of this study have clinical applicability and sound a cautionary note regarding the use of combination protocols in rTMS treatment, given the greater time and expense of bilateral treatments.