Factors That Influence Patients' Decisions About Repetitive Transcranial Magnetic Stimulation as a Treatment Option for Treatment-Resistant Depression: Protocol for a Prospective Mixed Methods Cohort Study.

Background: Treatment-resistant depression (TRD), affecting approximately 20% to 30% of individuals with major depressive disorder, is associated with significant disability, reduced quality of life, and an increased risk of hospitalization and suicide. Repetitive transcranial magnetic stimulation (rTMS), a noninvasive neuromodulation therapy, has demonstrated strong efficacy for TRD but is typically limited to research contexts or private clinics. Existing research on patient perspectives on rTMS is limited and largely retrospective, focusing on individuals who have already undergone treatment. As a result, little is known about the factors that influence patients' decisions to accept or decline rTMS at the time of referral, particularly within real-world clinical settings. Objective: This study aims to address the gap in the literature by prospectively examining decision-making processes surrounding rTMS in a community hospital outpatient clinic. Methods: This prospective mixed methods cohort study will recruit 30 adults with TRD referred to a public rTMS clinic. Participants will be stratified based on their decision to opt in or out of treatment. Data collection will include hybrid card sorting interviews, self-report questionnaires (assessing depression, well-being, cognitive flexibility, decisional conflict, and health literacy), and medical chart reviews. Each participant will complete a baseline and 6-month follow-up interview and survey. Qualitative data will be analyzed using constant comparative analysis, informed by bounded rationality and prospect theory. Quantitative data will be analyzed using bivariate statistics and hierarchical cluster analysis to identify patterns in decision-making factors. Results: This study is being funded by a charitable donation from Jack and Pat Kay to Humber River Health, which is also supporting the establishment of the rTMS clinic, committed to in April 2024. Recruitment commenced in December 2025 and is expected to conclude in December 2026; no participants have been enrolled as of February 2026. Conclusions: To the best of our knowledge, this is the first study to prospectively examine decision-making regarding rTMS in a real-world, publicly funded clinic including both individuals who initiate and those who decline treatment. The findings may inform the development of patient educational and engagement materials and highlight gaps in patient-physician communication during the rTMS decision-making process.