Clinical predictors of standard and accelerated theta burst rTMS treatment response in depression: an analysis from a multicentre RCT.

Objectives: Our group conducted a single-blind, controlled, multi-site trial, wherein participants with treatment-resistant depression were randomised to standard 10 Hz rTMS, applied to the left dorsolateral prefrontal cortex (DLPFC), or accelerated bilateral TBS (aBLTBS), applied sequentially to the right then left DLPFC. We present a secondary analysis of this trial, investigating clinical predictors for treatment response.

Methods: Logistic regression analysis explored the relationship between TMS response and, adjusted for baseline depressive symptom severity: suicidality, current episode duration, age, sex, and presence of melancholia and psychosis. The relationship between self-reported past ECT response and current rTMS treatment response was evaluated with McNemar's test.

Results: Adjusted response status to aBLTBS, but not standard rTMS, is influenced by duration of current episode (aBLTBS OR 0.9945, p = 0.0417 vs. rTMS OR 0.9973, p = 0.2870). No other differential response predictors were identified.

Conclusions: There are no clinically significant differential response predictors to standard rTMS or accelerated TBS treatment protocols. Accelerated TBS or standard rTMS may be effective in treatment-resistant depression, including in patients with previous ECT non-response, and psychosis may lower the odds of treatment response. Given the overall time efficiency in delivering accelerated TBS, this may further strengthen the argument for its broader clinical adoption.