Utility of Repetitive Transcranial Stimulation as an Augmenting Treatment Method in Treatment-Resistant Depression

About 30 to 46% of patients with major depressive disorder (MDD) fail to fully respond to initial antidepressants. Treatment-resistant depression (TRD) is a severely disabling disorder with no proven treatment options; novel treatment methods like rTMS can be used as augmentation to ongoing pharmacotherapy or as a solitary method of treatment. To evaluate the utility of repetitive transcranial magnetic stimulation as an augmenting method in TRD. 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 intensity of 110% of 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. At the end of 4 weeks, 19 patients completed the 4-week 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 four patients reported headache, but there was no discontinuation due to adverse effects. The study indicates the potential utility of rTMS as an augmenting agent in TRD. Adequately powered, randomized controlled trials are necessary to evaluate the role of rTMS in TRD.