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Updated: Jan 12, 2026
Conventional Repetitive Transcranial Magnetic Stimulation for Depression: A Step-by-Step Protocol
Published on: November 21, 2025
Trajectories of response to bilateral rTMS in late-life depression
Erin Adler1, Daniel M Blumberger2, Xiao Chen3
1Institute of Medical Science, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada; Temerty Centre for Therapeutic Brain Intervention, Campbell Family Research Institute, Centre for Addiction and Mental Health, 1001 Queen St. W, Toronto, Ontario, M6J 1H4, Canada.
Background:
Late-life depression is often resistant to standard treatment (LL-TRD) and presents unique clinical challenges due to comorbidities and cognitive decline. Repetitive transcranial magnetic stimulation (rTMS) is a promising option, yet responses are variable. Identifying trajectories of symptom change in LL-TRD in response to rTMS may clarify this heterogeneity and guide more personalized interventions.
Methods:
This secondary analysis of a randomized rTMS trial in late-life depression used group-based trajectory modeling to identify depressive symptom response patterns. 172 participants aged 60+ were randomly assigned to one of two protocols: (1) bilateral rTMS, with low-frequency stimulation applied to the right dorsolateral prefrontal cortex (DLPFC) and high-frequency stimulation to the left; or (2) bilateral theta burst stimulation, with continuous TBS on the right DLPFC and intermittent TBS on the left. Multinomial regression identified baseline characteristics associated with trajectory membership.
Results:
Four symptom trajectories were identified: Nonresponse, Partial Response, Linear Response and Rapid Response. Relative to Partial Response, higher Montgomery-Åsberg Depression Rating Scale (MADRS) scores were associated with lower odds of Rapid (OR = 0.79, 95 %CI:0.69-0.90) and Linear Response (OR = 0.87, 95 %CI:0.78-0.97), and higher odds of Nonresponse (OR = 1.33, 95 %CI:1.16-1.52). Benzodiazepine use was associated with lower odds of Linear Response (OR = 0.22, 95 %CI:0.08-0.56), while higher baseline anxiety was associated with higher odds of Nonresponse (OR = 1.13, 95 %CI:1.01-1.26).
Conclusion:
This study identified four distinct rTMS response trajectories in LL-TRD and found that greater baseline depression severity and anxiety were associated with worse trajectories. These results support early clinical profiling to identify individuals at risk for nonresponse.
Clinicaltrials:
gov identifier NCT02998580.
