Utility of repetitive transcranial magnetic stimulation as an augmenting treatment method in treatment-resistant depression

Background: About 30-46% of patients with major depressive disorder (MDD) fail to fully respond to initial antidepressants. Treatment-resistant depression is a severely disabling disorder with no proven treatment options; novel treatment methods, such as repetitive transcranial magnetic stimulation (rTMS) can be used as augmentation to ongoing pharmacotherapy or as a solitary method of treatment. Aim: To evaluate the utility of rTMS as an augmenting method in treatment-resistant depression. Materials and Methods: In an open-label study, 21 patients with DSM-IV MDD without psychotic features who had failed to respond to an adequate trial of at least 2 antidepressants were given rTMS therapy for 4 weeks keeping the dose of pre-existing antidepressants unchanged. High-frequency (10 Hz) stimulations were delivered over left dorsolateral prefrontal cortex at an intensity of 110% of the patient's motor threshold. Treatment response was defined as a reduction in score on the Hamilton Rating Scale for Depression (HAM-D) from baseline to end of treatment. Secondary efficacy measures included scores on the Clinical Global Impressions-Change and -Severity scales. Results: At the end of 4 weeks, 19 patients completed the 4 weeks study and were assessed. In ITT analysis the mean HAM-D17 scores were reduced from 30.80±5.00 to 19.00±6.37 (t=8.27, P<0.001). Only 4 patients reported headache but there was no discontinuation due to adverse effects. Conclusions: The study indicates the potential utility of rTMS as an augmenting agent in treatment-resistant depression. Adequately powered, randomized controlled trials are necessary to evaluate the role of rTMS in treatment-resistant depression.