Any discussion of electroconvulsive therapy (ECT) inevitably involves the use of superlatives. ECT is the oldest of all biological treatments for psychopathology, the most effective for severe depression, and the most controversial. Since ECT was introduced in 1938, major advances in our understanding of neurophysiology and psychopathology, together with some serendipity, have led to many new pharmacologic treatments for depression. Nevertheless, as many as 1 in 5 patients with depression fail to respond to antidepressant medication (1,2). While ECT may be effective for these patients, its cognitive side effects and invasive nature make ECT unacceptable to many. New approaches to treating severe medication-resistant depression are needed.

Apart from psychotherapy, which may not be appropriate for patients with the most severe depression, few nonpharmacologic alternatives to antidepressant medications exist.

Manuscript received and accepted
June 2001.
¹Clinical Director, Regional Mood Disorders Program, Department of Psychiatry, McMaster University, Hamilton, Ontario, Canada.
Address for correspondence: Dr G Hasey, St. Joseph's Healthcare Hamilton,
Centre for Mountain Health, 100 West 5th Street, Hamilton, ON L8N 3K7

Vagus nerve stimulation (VNS), an experimental adjunctive treatment for epilepsy (3,4), has been reported to have antidepressant effects in an open trial (5). The device requires surgical implantation, however, and double-blind controlled clinical trials demonstrating antidepressant efficacy are still lacking. Another new technology that holds promise as a treatment for mood disorder, and is somewhat better-studied than VNS, is transcranial magnetic stimulation (TMS). TMS, which employs magnetic energy to alter cortical neuronal activity, has been shown to have significant antidepressant efficacy in several randomized, double-blind, sham-controlled TMS trials (6–8).

TMS Background

Brief History

Although attempts to create an electromagnetic brain stimulator date back to the 19th century, an effective TMS device was first built in 1985 by Anthony Barker at the University of Sheffield. Designed to function as a neurodiagnostic tool, the TMS prototype could produce an evoked potential in muscle tissue by activating neurons in the motor cortex. Newer coil designs created more focused magnetic fields that were then used to map regions of cortical involvement in functions such as memory (9), vision (10), and muscle control (11).