Does switching between high frequency rTMS and theta burst stimulation improve depression outcomes?

Abstract

To the editor, We read with interest recent articles in Brain Stimulation, reporting on the antidepressant effects of theta burst stimulation (TBS) applied in accelerated schedules [1,2] and the efficacy comparison between unilateral and bilateral repetitive transcranial magnetic stimulation (rTMS) approaches [3]. We recently reported a multisite randomized controlled trial comparing the antidepressant efficacy of accelerated bilateral TBS applied at 80% or 120% of the resting motor threshold (RMT) and left-sided 10 Hz rTMS applied at 120% RMT [4]. The increasing evidence base supporting TBS's antidepressant effects has seen it gain acceptance as an alternative to standard left-sided 10 Hz rTMS in treatment-resistant depression (TRD). Little is known whether TRD patients who do not experience antidepressant benefits with a standard course of rTMS might do so with a subsequent course of TBS, or vice-versa. Given that approximately 60–80% of patients who undergo a course of left-sided 10 Hz rTMS can expect to experience depression treatment response [3,5], this is a clinically relevant knowledge gap for which minimal evidence-based guidance exists. One way to address this is to evaluate non-responders’ treatment outcomes to a crossover course of the alternate stimulation protocol. To our knowledge, such a crossover study has not been reported.