Transcranial magnetic stimulation

Transcranial magnetic stimulation (TMS) is a noninvasive treatment that uses a rapidly changing magnetic field to induce weak electric currents in the cerebral cortex and stimulate nerve cells.

There is considerable evidence to support TMS for patients with major depression who have not responded to or have only partially responded to antidepressants. There is insufficient evidence to support TMS as first-line treatment of major depression, and its role in preventing relapse of depression is unclear. TMS is less effective than electroconvulsive therapy (ECT) for more severe cases of major depression.

TMS is a relatively new treatment and its application to other psychiatric disorders, including schizophrenia or obsessive compulsive disorder, is under investigation.

TMS is administered by trained psychiatrists in an outpatient setting and does not require anaesthesia. Treatment is administered as a series of repeated pulses (repetitive TMS [rTMS]). The frequency of treatment sessions and total duration of the treatment course is variable and determined by the treating psychiatrist, but is usually administered as daily treatment sessions over a course of 2 to 4 weeks. Further courses of TMS may be considered, but the role of maintenance TMS is unclear.

TMS is generally well tolerated; induction of a seizure is an extremely rare adverse effect. Depending on stimulus parameters, patients may experience local scalp discomfort and headaches. Unlike ECT, there are few interactions between psychotropics and TMS, but any changes to pharmacotherapy should be made under the guidance of the treating psychiatrist.

Evidence to support the use of TMS in pregnancy is limited, but suggests it improves symptoms of depression and is unlikely to cause harm.