 A promising new approach to enhance efficacy involves combining LFR-TMS and HFL-TMS in a sequential manner. We describe this as sequential bilateral rTMS SB-rTMS. We have recently published the results of the first substantial evaluation of SB-rTMS showing not only a superiority to placebo in TRD but also a therapeutic response that is substantially superior to response rates in most of the published studies of unilateral rTMS 50 of patients achieving standard criteria for clinical response compared to usually 30 in most studies. In this proposed research study, we will directly test the hypothesis that SB-rTMS produces a greater therapeutic response than HFL-TMS and compare both of these forms of stimulation to placebo i.e., sham stimulation. 