Background: Bipolar disorder (BD) is characterized by persistent cognitive deficits. These deficits contribute to functional impairment and often respond poorly to pharmacotherapy. Although deep transcranial magnetic stimulation (dTMS) has demonstrated antidepressant efficacy, there is limited knowledge about its cognitive effects and comprehensive clinical performance in BD. In this study, we assessed the cognitive outcomes, clinical efficacy, and safety of H1-coil dTMS in BD patients. Methods: In this randomized, double-blind, sham-controlled trial, 100 inpatients with BD received 4 weeks of active or sham H1-coil dTMS. The MATRICS (Measurement and Treatment Research to Improve Cognition in Schizophrenia) Consensus Cognitive Battery (MCCB) was used to investigate the cognitive function, and the 17-item Hamilton Depression Rating Scale (HDRS-17) was used to assess depressive symptoms from baseline to week 4. Results: Both groups, active and sham dTMS, showed significant cognitive improvements across most domains (p 0.05). At the endpoint, the active dTMS group showed statistically significantly lower HDRS-17 scores and a higher response rate than the sham group (mean difference = 2.94, 95% CI 0.10, 5.78, p = 0.04); 50% vs. 24%; OR = 3.17, 95% CI 1.35, 7.44, p = 0.007). All treatments demonstrated a favorable safety profile, with only mild and transient adverse effects. Conclusions: In patients with BD, active dTMS was well-tolerated and was associated with a higher response rate and statistically significant (albeit modest) lower depressive symptom scores compared to sham stimulation, without inducing cognitive adverse effects. However, no specific cognitive benefit beyond its antidepressant effect was established. Overall, these results indicate that dTMS has potential as an adjunctive treatment option for bipolar depression, particularly when medications are limited or poorly tolerated. Clinical Trial Registration: NCT06524505. Registered 23 July, 2024, https://clinicaltrials.gov/study/NCT06524505.
Chu et al. (2026) studied this question.