Accelerated Transcranial Magnetic Stimulation in Treatment-Resistant Depressed Patients

Depression is the leading cause of disability worldwide and around 800,000 suicides occur each year. According to the World Health Organization, major depressive disorder (MDD) is expected to be the leading cause of the global burden of disease by 2030. One third of MDD patients do not respond to first-line pharmacologic and psychotherapeutic antidepressant treatments. New antidepressant treatments that are safe, tolerable, fast-acting, durable and effective are needed. Transcranial magnetic stimulation (TMS) is a promising form of non-invasive brain stimulation with rapid antidepressant and suicide prevention effects in MDD. TMS applied to the left dorsolateral prefrontal cortex (DLPFC) is a non-invasive brain stimulation technique approved by the US Food and Drug Administration (FDA) for treatment-resistant depression. TMS involves passing an electric current through a magnetic coil placed on the surface of the scalp, producing a high-intensity magnetic field that travels through the scalp, skull and meninges, stimulating neuronal tissue. This in turn causes changes in functional connectivity. The mechanism of TMS on core depressive symptoms is hypothesized to be mediated in part through indirect inhibitory functional connectivity from the left DLPFC to the subgenual anterior cingulate cortex (sgACC).