Adjunctive duration-doubled transcranial direct current stimulation for the treatment of depressive patients with suicidal ideation: study protocol for a double-blind, randomized, sham-controlled trial.

"availability of data and materials {29} data relevant for publications will be published on a suitable repository (e g zenodo"

"Declarations Ethics approval and consent to participate {24}The study protocol was approved by the Ethics committee of Shanghai Mental Health Center at Shanghai Jiao Tong University (Ethics approval number: 2021-72R). The aims and process of the trial, possible results, and risks will be explained to the participants. Written informed consent will be obtained from all participants, including a written informed consent for use of biological specimens (see above item 33). Consent for publication {32}Not applicable. Competing interests {28}The authors declare that they have no competing interests. Competing interests {28} The authors declare that they have no competing interests."

"Funding {4} This study was supported financially by Research Proposal for the Capability Promotion Project for Research-Oriented Doctor at Shanghai Mental Health Center (2021-YJXYS-06). The materials including tDCS devices were supported by Shanghai “Science and Technology Innovation Action Plan” Medical Innovation Research (21Y11905600); Shanghai "Science and Technology Innovation Action Plan" Natural Science Foundation of Shanghai (21ZR1455100) and Davis Family Gift Fund. The professional service was supported by National Key R&D Program of China (2016YFC1307100); the National Natural Science Foundation of China (81930033); the Key Project of Clinical Research Center of Shanghai Mental Health Center (CRC2018ZD02); Shanghai Municipal Science and Technology Major Project (2018SHZDZX05), the Project of “Psychobehavioral Disorder” Clinical Research Center of Shanghai Jiao Tong University School of Medicine (2019-yxy-01) and Innovative Research Team of High-level Local Universities in Shanghai. The study protocol has undergone external peer review by the funding agency, as part of the peer review process. The funding agency had no role in the planning of the study design and will not be involved in data collection and analysis, decision to publish or preparation of the manuscript."

"Trial registration The trial protocol is registered with ClinicalTrials.gov under protocol registration number NCT05555927. Registered on September 25, 2022."