D-Cycloserine Augmentation of Intermittent Theta Burst Stimulation (iTBS) in Depression (COGENT)

D-cycloserine (DCS) is a partial NMDA receptor agonist that has demonstrable impact on rTMS and TBS's neuromodulatory effects. Participants will be asked to orally ingest one capsule 2-hours prior to their scheduled iTBS treatment time.

Intermittent Theta Burst Stimulation (iTBS) will be administered with a magnetic stimulator using a figure-of-8 coil or equivalent FDA-approved device. Initial treatment coil localisation and individual calibration of stimulation intensity will be conducted by TMS-trained investigators/staff using standard approaches.67,68 Stimulation intensity will be at 90% of the individual's calibrated resting motor threshold. iTBS treatment session delivers 600 pulses and is approximately 3½ minutes in duration. The total pulse number applied over a course of 20 treatments will be 12,000. This regimen is analogous with the iTBS protocol approved by the US FDA to treat TRD.