Roughly half the people experiencing major depressive disorder also experience treatment-resistant depression, depression that does not respond to medication or talk therapy. Transcranial magnetic stimulation is approved by the U.S. Food and Drug Administration to treat this type of depression. However, the transcranial magnetic stimulation protocol currently in use is only moderately effective.

Now scientists at Stanford University have developed a more efficient method of administering transcranial magnetic stimulation compared to the FDA-approved treatment. Dubbed SNT — for Stanford neuromodulation therapy — the technique successfully induced remission in almost 80 percent of participants with severe depression, in a recent study.

Instead of one treatment per day, patients are given multiple short treatments per day; and treatment is administered over five consecutive days, rather than six weeks.

Study participants often reported feeling better within a few days of starting SNT. This could have a role in treating people who are in a psychiatric emergency in emergency departments and psychiatric hospitals, Nolan Miller, senior author of the study, told TheDoctor. “The period right after hospitalization is when the risk of suicide is highest.”

How it works
Unlike traditional transcranial magnetic stimulation, SNT uses magnetic resonance imaging to identify the optimal target in the brain for magnetic stimulation. Almost 2,000 magnetic pulses are administered per treatment session, many more than the 600 administered in the current protocol. Instead of one treatment per day, patients are given multiple short treatments per day. Treatment is administered over five consecutive days, rather than six weeks.

During SNT, magnetic pulses are applied to the dorsolateral prefrontal cortex, a region of the prefrontal cortex that is connected to a part of the brain that is overactive in those with depression, the subgenual cingulate. SNT strengthens this connection, allowing the prefrontal cortex greater control over the subgenual cingulate.

Twenty-nine people with treatment-resistant depression received either active SNT or a sham control treatment. Neither the investigators nor the participants knew which treatment was administered.

Those in the study had had depression for an average of nine years. They had tried antidepressants, and either the medication had stopped working or didn't ever have any effect. During the trial, those who were on antidepressants continued with their usual regimen; those who were not taking antidepressants did not start.

The primary outcome was a change in the score on the Montgomery-Asberg Depression Rating Scale four weeks after treatment. The 14 participants who received the active SNT treatment had a mean reduction of about 50 percent in their score, while those who received the sham treatment had a mean reduction closer to 11 percent. Within four weeks of treatment, 11 of the 14 participants who received the active treatment met the U.S. Food and Drug Administration criteria for remission, while only two of the 15 participants in the sham treatment group met the criteria.

“It works well, it works quickly and it’s noninvasive. It could be a game changer,” Williams, an assistant professor of psychiatry and behavioral sciences at Stanford, said in a statement. The team is planning larger studies including hundreds of people.

The study is published in the American Journal of Psychiatry.