Safety, Tolerability, and Effectiveness of High Doses of Adjunctive Daily Left Prefrontal Repetitive Transcranial Magnetic Stimulation for Treatment-Resistant Depression in a Clinical Setting

Objective: Daily left prefrontal repetitive transcranial magnetic stimulation (rTMS) recently received Food and Drug Administration (FDA) approval for the treatment of depression and offers an alternative to traditional approaches. This approval was based on a study using 3000 stimuli per day (15,000 stimuli per week) in adults with unipolar depression not taking antidepressant medications. Several meta-analyses suggest a dose-response relationship with TMS. This study was carried out before US FDA approval to test the safety, tolerability, and effectiveness of adjunctive high-dose left prefrontal rTMS in a clinical setting with particular attention to safety of higher doses and potential interactions with antidepressant medications, speed of response, and effects on suicidality. Method: We enrolled 19 patients who were in a current major depressive episode with treatment-resistant unipolar or bipolar depression and treated them in their acute episode and in a maintenance fashion for 18 months. The patients received daily left prefrontal rTMS at 120% resting motor threshold, 10 Hz, 5 seconds on, and 10 seconds off and for a mean of 6800 stimuli per session (34,000 stimuli per week), more than twice the dose delivered in the pivotal FDA trial. All patients continued antidepressant medication throughout the rTMS treatment; thus rTMS was an adjunctive treatment. We measured adverse effects, depression, quality of life, suicidal ideation, and social and physical functioning. Results: These higher rTMS doses were well tolerated without significant adverse effects or adverse events. All measured dimensions showed improvement, with many showing improvement in 1 to 2 weeks. Of perhaps most importance, suicidal ideation diminished in 67% of the patients after just 1 week. Conclusions: These uncontrolled data suggest that higher doses of daily left prefrontal rTMS may safely be used in outpatients with major depressive episode even as an adjunctive treatment.