Efficacy of twice-daily vs once-daily sessions of repetitive transcranial magnetic stimulation in the treatment of major depressive disorder: a retrospective study

PURPOSE: There is no clinical consensus on the optimal protocol for the treatment of major depressive disorder (MDD) using repetitive transcranial magnetic stimulation (rTMS). Accelerated protocols using more than a single session of treatment per day have been suggested as a means to reduce the overall length of time required for rTMS therapy. The objective of this study is to compare the treatment outcomes of patients with MDD who received two sessions of rTMS per day vs those who received one session per day, keeping the overall number of delivered pulses constant. PATIENTS AND METHODS: In a retrospective study, we compared treatment outcomes of 36 patients with MDD who received 30 sessions of high-frequency (10 Hz) rTMS over the left dorsolateral prefrontal cortex. Patients received 3,000 pulses per session (5 s trains, 25 s intertrain interval) at 110% of resting motor threshold using a figure-eight coil. Patients received either two rTMS sessions per day (n=17) or one session per day (n=19). Depression symptoms were assessed by a psychiatrist using the Hamilton Rating Scale for Depression at baseline and after every 10 sessions of rTMS. RESULTS: The majority of patients in both groups responded to treatment, and there was a trend toward greater response rate in the twice-daily (TD) group (82.4%) compared to the once-daily (OD) group (52.6%). TD stimulation was tolerable for patients and produced no adverse side effects. Patients in the TD group experienced an improvement in symptoms faster than the OD group due to the accelerated therapy period. CONCLUSION: Administration of two rTMS treatment sessions per day is tolerable for patients and does not seem to be inferior in efficacy to a OD protocol. TD administration has the benefit of producing symptom improvement over a shorter time span and requires fewer visits to the clinic.