Wearable-Based Assessment for Relapse Prediction Following Repetitive Transcranial Magnetic Stimulation for Depression: Protocol for a Feasibility Study (WARN-D Study) (Preprint)

A significant proportion of patients with major depressive disorder do not achieve remission after two antidepressant trials and are considered to suffer from Treatment-Resistant Depression (TRD). Repetitive transcranial magnetic stimulation (rTMS) is an effective treatment for TRD. However, relapse rates among remitters within the first year post-treatment are significant, and there are no validated markers of relapse. Wearable devices have shown positive results for longitudinal monitoring of health metrics and may be a promising tool for an early detection of relapse following rTMS treatment.

To evaluate the feasibility of a wearable device (Oura ring) to monitor individuals receiving rTMS treatment for depression and its utility to detect early signs of depressive relapse in a 6-month follow-up period.

This single-arm pilot study will recruit 20 outpatients with a major depressive episode receiving rTMS at St. Joseph’s Healthcare Hamilton, Ontario, Canada. Participants will be required to wear an Oura ring throughout the treatment course and during the six-month follow up. Clinical assessments, including Montgomery-Åsberg Depression Rating Scale (MADRS), Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), Insomnia Severity Index (ISI), and World Health Organization-Five Well-Being Index (WHO-5), will be collected at baseline, treatment end, and 3- and 6-month follow-ups, alongside bi-weekly PHQ-9 and GAD-7 scores. The primary outcomes are feasibility metrics (i.e., recruitment, adherence, retention, missing data, usability). Secondary outcomes will include the utility of wearable-based data for predicting relapse.

The study was funded in December 2025, and data collection will start following Ethics Approval.

This study will provide initial evidence on the feasibility and utility of a wearable-based digital phenotyping in individuals receiving rTMS for TRD. Our findings will inform the design of future large-scale studies aimed at wearable-supported relapse prevention and precision monitoring in depression care.