Objectives: Repetitive transcranial magnetic stimulation (rTMS) of the left dorsolateral-prefrontal cortex (DLPFC) exerts antidepressant effects. In this randomised controlled clinical trial we aimed to test the safety and therapeutic efficacy of bilateral theta-burst stimulation (TBS) as an add-on therapy to standard treatment of major depression.
Methods: Fifty-six patients diagnosed with a moderate to severe depressive episode received 15 daily treatments of either rTMS (110% motor-threshold; rightDLPFC, 1000 stimuli at 1 Hz + leftDLPFC, 1000 stimuli at 10 Hz), theta-burst stimulation (80% motor-threshold; rightDLPFC, continuous TBS, 1200 stimuli + leftDLPFC, intermittent TBS, 1200 stimuli), or sham TMS (N = 17, sham coil with the TBS protocol).
Results: There was no significant effect in the primary outcome measures (change of the 21-item Hamilton Rating Scale for Depression). However, there was a tendency towards an increased responder rate at the end of the follow-up period for both active treatments as compared to sham, and this tendency was most pronounced for the TBS group.
Conclusions: This pilot study did not reveal significant advantages of bilateral TBS or rTMS over sham treatment as an add-on treatment for major depression. A tendency towards a superior effect of bilateral TBS at the end of the follow-up period may warrant further studies.
Keywords: bilateral; depression; prefrontal cortex; repetitive transcranial magnetic stimulation; theta burst.