Study of a Repetitive Transcranial Magnetic Stimulation (rTMS) Device for the Treatment of Major Depressive Disorder

This trial will test the safety and efficacy of a rTMS device for the treatment of major depressive disorder. Major depression is one of the most prevalent and profoundly debilitating diseases worldwide. In a recent report, it is estimated that by the year 2020, depression will be second only to heart disease in magnitude of disease burden as determined by disability-adjusted life years. Despite major advances in the treatment of depression in the last three decades, further improvements are needed. For instance, with respect to antidepressant pharmacotherapy, only 1/3 of patients are estimated to have a nearly full resolution of their clinical symptoms with their first medication trial. Indeed, partial remission or lack of response to treatment is experienced by the majority of patients. Even with serial trials of antidepressant medication, at least 10 to 15% of patients with major depression are estimated to experience limited benefit and remain chronically depressed with significant psychosocial morbidity. Some patients cannot tolerate the dosage and duration of antidepressant treatments required for treatment trials to be considered adequate. In such patients, intolerance of somatic treatments for major depression leads to chronicity and impaired function, and likely hinders long-term compliance with treatments. For many patients with treatment resistant depression (TRD), more complex regimens of polypharmacotherapy, or the use of electroconvulsive therapy (ECT) are the only currently available treatment options. Repetitive transcranial magnetic stimulation (rTMS) is a promising alternative to treatments such as ECT or pharmacotherapy for patients presenting with MDD. An rTMS procedure is non-invasive, does not require anesthesia, and may be delivered in an appropriately staffed outpatient setting. By creating a time-varying magnetic field that is unimpeded by the scalp and skull, TMS can focally and painlessly stimulate the cortex of awake individuals. Through the principle of magnetic induction, the localized pulsed magnetic field generated in the coil at the surface of the head induces an electrical current that depolarizes underlying superficial neurons. It is widely thought that rTMS produces its behavioral effects solely through the induction of current flow in cortex. Several factors have driven the investigation of rTMS for the treatment of MDD. Early reports of changes in mood in normal participants, the non-invasive nature of rTMS, the favorable side effect profile compared to ECT, and the non-response of a number of MDD patients to pharmacotherapy and/or ECT, all have likely played a role. Since the initial studies, there has continued to be high interest in rTMS as an antidepressant treatment. Multiple trials have been conducted from researchers in diverse environments around the world. However, until now, there have been no rigorously conducted large, multicenter rTMS clinical trials in the treatment of patients with MDD. Because the published research has largely been conducted in single centers, the sample sizes in these antidepressant trials have been small. However, the majority of more than 20 reports have found modest to large antidepressant effects that increase over the trial period. By design, this trial will provide more robust information regarding the antidepressant effect of rTMS in the adult population of MDD patients.