28 Nov 2021

How brain magnets can help relieve depression

From Sunday Morning, 11:18 am on 28 November 2021

Depression is the leading cause of disability around the world, with World Health Organization global estimates suggesting that 5 percent of adults worldwide suffer in some way. 

Around half of those people with depression have treatment-resistant depression. But researchers at the Stanford University School of Medicine say they are now able to treat depression in 80 percent of participants with treatment-resistant depression by stimulating their brains with magnets.

And the treatment only takes days to complete. 

Dr. Nolan Williams is the Director of the Stanford Brain Stimulation Lab.

Dr. Nolan Williams is the Director of the Stanford Brain Stimulation Lab. Photo: Supplied/Stanford University

Nolan Williams is the study's co-author and assistant professor of psychiatry at Stanford. He joined Sunday Morning to discuss the procedure, which is called Stanford Neuromodulation Therapy (SNT).

Williams says Transcranial Magnetic Stimulation (TMS) has been around since the 1990s but they’ve since learned a lot more about how the brain and treatment works.

“To its credit, it works quite well but it takes quite a while to get to a level where it's actually anti-depressant. One hour a day, five days a week, for around six weeks.

“What we’ve figured out how to do is compress that six weeks into a single day and find the person's best TMS target based off their brain connectivity using magnetic resonance imaging, MRI. We’ve employed a much more accurate way of doing it.”

He says a person can come in, get a brain MRI, get stimulated over a series of sessions over a couple of days and be well after just one day or two or three.

“That’s quite useful in the context of psychiatric emergencies, to get them out of being in that place – mentally – in a very short period of time.”

Williams says earlier approaches used an average of the human brain to administer the therapy, but no two brains are the same and they can accurately find the precise area to place the magnetic pulses.

“If you’re a pianist and you’ve been a pianist your whole life, the area of your brain that deals with motor cortex function, hand function, is expanded. If I used a TMS coil and pinged and deliver pulses in your motor cortex, you have this giant area that’s dedicated to hand function. If your next-door neighbour is a world class martial artist who’s been kicking for their whole life, their foot representation in their motor cortex is going to be much larger and the hand is going to be much smaller.

“Our experiences can change what amount of our brains are dedicated to certain functions and how our brains are connected. It’s the same sort of thing in the mood system.”

While the treatment is effective and promising, TMS comes with a small risk of causing seizures. Williams says no patient thus far has had one in their treatment, but they can’t rule out the risk.

“But a big part of the risk for TMS causing a seizure is operator error and this treatment takes a lot of the operator error potential out because it’s so neuro-navigated… it’s all so well controlled and automated in that way.”

And it’s nonetheless the lowest risk treatment currently in operation with a one in 30,000 risk of seizure. And the benefits are enormous.

“With our methods, if you treat ten people eight of them are going to get better from this. That’s dramatic, we haven’t really seen anything like that in psychiatry.”

Although the treatment is safe and effective, it is still a ‘last resort’ for people from whom other treatments don’t work because of the prohibitive cost.

“It’s hard to justify this elaborate treatment in people who’ve not failed oral antidepressants which are quite cheap these days… until you can justify something like this from a cost standpoint, it’s hard to say that should be first line.”

It’s also not a silver bullet. Williams says TMS is a temporary fix and the brain slowly drifts back into its older habits.

“It’s a big question for the field, we need to figure out ways to use the stimulation to keep people well.”