RecruitingPhase 1Device studyPharmacologic Augmentation of TMS for Depression With D-serineThe goal of this study is to test whether combining D-serine with 30 treatments of a) iTBS and b) 18-Hz protocols will enhance clinical outcomes compared to rTMS with placebo (i.e., sugar pill). The investigators hypothesize that NMDA receptor activation via D-serine combined with repeated sessions of rTMS will produce greater clinical outcomes than iTBS with placebo and 18-Hz with placebo.