Efficacy and safety of low-frequency repetitive transcranial magnetic stimulation for bipolar depression: a study protocol for a multicenter, double-blind, randomized, sham-controlled trial - Noda, Takamasa; Nishikawa, Masako; Matsuda, Yuki; Hayashi, Daisuke; Kito, Shinsuke (Frontiers in Psychiatry, 2025)