A double-blind pilot dosing study of low field magnetic stimulation (LFMS) for treatment-resistant depression (TRD)

Abstract Background Low field magnetic stimulation is a potentially rapid-acting treatment for depression with mood-enhancing effects in as little as one 20-min session. The most convincing data for LFMS has come from treating bipolar depression. We examined whether LFMS also has rapid mood-enhancing effects in treatment-resistant major depressive disorder, and whether these effects are dose-dependent. Objective/Hypothesis We hypothesized that a single 20-min session of LFMS would reduce depressive symptom severity and that the magnitude of this change would be greater after three 20-min sessions than after a single 20-min session. Methods In a double-blind randomized controlled trial, 30 participants (age 21–65) with treatment-resistant depression were randomized to three 20-min active or sham LFMS treatments with 48 h between treatments. Response was assessed immediately following LFMS treatment using the 6-item Hamilton Depression Rating Scale (HAMD-6), the Positive and Negative Affect Scale (PANAS) and the Visual Analog Scale. Results Following the 3rd session of LFMS, the effect of LFMS on VAS and HAMD-6 was superior to sham ( F  (1, 24) = 7.45, p  = 0.03, Bonferroni–Holm corrected; F  (1, 22) = 6.92, p  = 0.03, Bonferroni–Holm corrected, respectively). There were no differences between sham and LFMS following the initial or second session with the effect not becoming significant until after the third session. Conclusions Three 20-min LFMS sessions were required for active LFMS to have a mood-enhancing effect for individuals with treatment-resistant depression. As this effect may be transient, future work should address dosing schedules of longer treatment courses as well as biomarker-based targeting of LFMS to optimize patient selection and treatment outcomes.