Comparative efficacy of high-frequency repetitive transcranial magnetic stimulation to left dorsolateral prefrontal cortex as an augmentation strategy versus pharmacological augmentation in non-psychotic, unipolar, treatment-resistant depression: A randomized controlled trial

BACKGROUND: Depression causes significant morbidity, disability and mortality, along with socioeconomic losses. Patients with depression who don’t remit even with the second trial of anti-depressants need optimization, combination or augmentation strategies. Pharmacological strategies sometimes have unacceptable adverse effects. AIM: The aim of this study is to compare the efficacy of high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) to left dorsolateral prefrontal cortex (DLPFC) with that of pharmacological augmentation strategies in unipolar non-psychotic treatment-resistant depression. METHOD: This is a randomized controlled trial. SUBJECTS: Cases of unipolar, non-psychotic, treatment-resistant depression between ages 20 and 60 years were taken. PERIOD OF STUDY: The study period was from November 2016 to May 2018. RANDOMIZATION: Cases diagnosed as per ICD-10 criteria by a qualified psychiatrist. Cases of treatment-resistant depression (100) were divided into two arms by using a random number generator: rTMS arm and treatment as usual (TAU) arm. INTERVENTION: HF-rTMS to left DLPFC (rTMS group) and pharmacological augmentation with lithium, serotonin-dopamine antagonist, buspirone or thyroxine. RESULTS: In the rTMS arm, 44 patients and in TAU arm 41 completed the study. After 4 weeks of treatment augmentation, rTMS and TAU groups showed response rates of 52% and 46%, respectively. The difference between the two groups in terms of number of responders at the end of 4 weeks is not statistically significant. Additionally, factors associated with good response to rTMS were absence of a family history of psychiatric illness, no concomitant psychoactive substance use, being first episode of depression and mild–moderate severity of illness. CONCLUSION: The study did not find rTMS augmentation to be significantly better than standard pharmacological augmentation therapies.