Weekly trajectories of antidepressant response to transcranial magnetic stimulation - A retrospective cohort analysis

Transcranial magnetic stimulation (TMS) is an established treatment for treatment-resistant depression, yet real-world weekly response trajectories remain understudied. This retrospective study examined dual-scale weekly antidepressant response patterns in a naturalistic clinical sample.

Chart review of patients with unipolar depression who received rTMS treatment in Regionspsykiatrien Gødstrup from March 2022 to July 2025. Depression severity was assessed weekly with Hamilton Depression Rating Scale-17 (HAM-D17) and Major Depression Inventory (MDI), from baseline through Week 6 (30 TMS sessions). Primary outcomes were weekly symptom changes, response and remission rates.

The sample comprised 56 patients (mean age 46 ± 16.62 years, 50 % female) with moderate to severe depression (baseline HAM-D17: 22.3 ± 5.80; MDI: 35.33 ± 6.80) and moderate treatment resistance (Maudsley Staging Method: 7.04 ± 1.67). Treatment completion rate was 85.7 % with a mean of 31.61 ± 7.82 sessions. HAM-D17 showed a stepwise improvement pattern, while MDI scores showed a linear improvement. Each additional week of TMS treatment increased MDI response and remission odds >1.5 fold. HAM-D17 weekly response odds were > 2; remission odds were non-significant. At end of treatment, response rates were 20 % (HAM-D17), 16 % (MDI), and 25 % (either scale); remission rates were 13 % (HAM-D17), 25 % (MDI), and 30 % (either scale). Treatment effect sizes were large (Hedges' g > 0.9) in both scales.

Our results support TMS effectiveness in naturalistic conditions, underscoring the importance of treatment duration in TMS treatment. The study highlights the importance of measurement-based care with multiple rating scales to capture treatment effects comprehensively. MDI was shown to be a sensitive instrument in monitoring TMS effectiveness.