Transcranial magnetic stimulation in psychiatry: Research and therapeutic applications

Transcranial magnetic stimulation (TMS) is a new, non-invasive procedure where a localized pulsed magnetic field to the surface of the head depolarizes underlying superficial neurons. The magnetic field is generated by passing powerful, brief electrical currents through a conducting coil, held close to the scalp. This electrically generated magnetic field passes unimpeded through the skull (transcranial) and is focused in the cortex (stimulation). The earliest research uses of TMS were in neurology, where TMS was used to examine central and peripheral nerve conduction as well as to study motor cortex. More recently, this technology has been widely used to map various brain functions such as visual information processing, language, memory, emotion, and movement. The ability to excite or inhibit local areas of the brain has raised the possibility of whether TMS might be a novel therapeutic tool for various psychiatric disorders. Here we review the methodology of TMS and its emerging research and therapeutic applications in psychiatry.