A clinical review of an effective approach for treatment-resistant depression.
Repetitive transcranial magnetic stimulation (TMS) is a useful clinical tool that is effective in patients with treatment-resistant depression. This noninvasive treatment is an option for patients with depression who have not found relief from other treatments, such as psychotherapy and antidepressants.
TMS technology was developed in 1985 and has been gaining clinical interest since then. Two-thirds of TMS patients experienced either full remission of their depression symptoms or noticeable improvements.1 An out-patient procedure, TMS does not have serious side effects.
Mechanism of Action
Approved by the US Food and Drug Administration in 2008, TMS uses an alternating current passed through a metal coil placed against the scalp to generate rapidly alternating magnetic fields. These pass through the skull nearly unimpeded and induce electric currents that depolarize neurons in a focal area of the surface cortex.
The magnetic field generated by TMS is comparable to that of a standard magnetic resonance imaging device (MRI), measured at approximately 1.5 to 3 Teslas. However, the TMS field is focal (beneath the coil), whereas the MRI field is large and fills the room housing the MRI device.