Treatment of Depression in the Elderly With Repetitive Transcranial Magnetic Stimulation (rTMS) Using Theta-burst Stimulation (TBS): Randomized, Double-blind, Sham-controlled, Clinical Trial

Recurrent transcranial magnetic stimulation (rTMS) is a consolidated procedure for the treatment of depression, with several meta-analyzes demonstrating its efficacy. The theta-burst stimulation (TBS) method is a modification of the usual rTMS protocol. As a new protocol, there are still few studies evaluating its efficacy in treatment of major depression, although a recently published meta-analysis has pointed to benefits of this therapeutic modality. To date, there are no studies published with this method for the treatment of geriatric depression. This study will be a randomized, placebo-controlled, double-blind clinical trial to evaluate the efficacy of theta-burst rTMS in the treatment of major depressive disorder in the elderly, randomizing 108 subjects to the experimental (TBS) and comparative (sham) groups. The coil will be positioned in the dorsolateral prefrontal cortex, with intermittent TBS (iTBS, stimulatory) mode on the left and continuous TBS (cTBS, inhibitory) on the right. Stimulation protocol consists of 1800 pulses on each brain hemisphere, totaling a ten minutes session. There will be 20 consecutive sessions, one a day, except on weekends and holidays. The cycle of continuous intervention will last approximately four weeks, after which applications with the same technique will be performed at the end of weeks 6, 8 and 12. Clinical outcome measures will be obtained on eight occasions: treatment baseline, and after 1, 2, 4, 6, 8 and 12 weeks of onset. The main clinical outcome will be measured using the Hamilton Depression Scale (HDRS), comparing baseline scores with those obtained after 6 weeks of treatment. As secondary endpoints, we will use the Global Clinical Impression Scale (CGI), the CIRS (Cumulative Illness Rating Scale), the Geriatric Depression Scale (GDS), the intermediate scores obtained on the HDRS scale, the Positive and Negative Affect Scale (PANAS), the Montgomery-Asberg Depression Rating Scale (MADRS), and variations in serum BDNF concentrations; all these evaluation tools have validated versions in Portuguese. As tolerability and safety parameters, the incidence of adverse events and the occurrence of manic/hypomanic symptoms will be evaluated by the Young Mania Scale (YMRS). TBS stimulation will be evaluated in terms of safety, tolerability and effectiveness for the treatment of major depression in the elderly, possibly becoming another therapeutic option useful for patients with poor response or contraindications to the use of antidepressants.