Older Age Associated with Better Antidepressant Response to Deep Transcranial Magnetic Stimulation

Background: TMS is increasingly used to treat major depression, but factors that predict better treatment outcomes remain unclear. We assessed the association between age and TMS response given inconsistent reports in the literature, as prior studies were limited by small sample size, heterogeneity, outdated TMS parameters, lack of assessment of deep TMS, and lack of an a priori hypothesis. We hypothesized that older age would be associated with better treatment response based on trends in recent large exploratory analyses. Methods: We conducted a naturalistic retrospective analysis of patients (n=378) ages 18-80 with depression (baseline Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR) > 5) who received a full course of TMS between 2014 and 2021. Response was assessed using percent reduction of QIDS-SR. The relationship between percent response or remission and age group was assessed using the chi-square test. Results: 85% of patients received the standard protocol of deep TMS to the left DLPFC. Antidepressant effectiveness of TMS was greater in older patients. The percent response and remission rates for the entire study sample increased with age (response: χ2=9.29, p=.026; remission: χ2=14.54, p=.0023). This trend was stronger in female patients (response: χ2=13.72, p=.0033; remission: χ2=16.32, p=.00098) and was not found in male patients (response: χ2=1.30, p=.73; remission: χ2=4.03, p=.26). Conclusions: Older age is associated with a better antidepressant response to deep TMS, particularly in female patients. This was demonstrated in a hypothesis-driven confirmation of prior exploratory findings in a large sample size with a homogeneous data collection protocol across all participants. Conflicts of Interest: SHS is a scientific consultant for Magnus Medical and a clinical consultant for Acacia Mental Health, Kaizen Brain Center, and Boston Precision Neurotherapeutics. SHS has jointly received investigator-initiated research funding from Neuronetics. SHS has also received investigator-initiated research funding from BrainsWay. SHS has served as a speaker for BrainsWay (branded) and PsychU.org (unbranded, sponsored by Otsuka). SHS owns stock in BrainsWay (publicly traded) and Magnus Medical (not publicly traded). SHS owns intellectual property involving the use of functional connectivity to target TMS. Funding: None Disclosures: None