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Dr. Jonathan Downar, right, demonstrates how to use repetitive transcranial magnetic stimulation to treat depression on senior technician Vanathy Niranjan at Toronto Western Hospital in Toronto on Thursday, June 19. (Darren Calabrese for the globe and mail)
Dr. Jonathan Downar, right, demonstrates how to use repetitive transcranial magnetic stimulation to treat depression on senior technician Vanathy Niranjan at Toronto Western Hospital in Toronto on Thursday, June 19. (Darren Calabrese for the globe and mail)

A high-tech tool to fight depression Add to ...

Almost 5 per cent of the population suffers from severe depression, a debilitating brain disease that makes it virtually impossible to get out of bed in the morning, and often literally, not figuratively, saps sufferers of the will to live.

There are currently two principal treatments: anti-depressant medications such as selective serotonin reuptake inhibitors (SSRIs); and therapy such as psychoanalysis and cognitive-behaviour therapy (CBT).

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There are also a couple of other forms of treatment, electro-convulsive therapy (ECT) and deep brain stimulation (DBS), but they are used on only a tiny minority of sufferers.

Sadly, not everyone gets treatment but, even among those who do, about one-third remain treatment-resistant, meaning they don’t get better despite trying a variety of medications, often in combination with therapy or ECT/DBS. But there’s some new hope on the horizon: Magnets.

Specifically, a treatment with the unwieldy name MRI-guided repetitive transcranial magnetic stimulation (rTMS for short) is creating some buzz.

The root causes of depression are complex – a combination of genetics, the environment in which we live, and triggers including stress or trauma.

To oversimply quite a bit: When a person is profoundly depressed, it’s because certain neurons in the brain misfire and alter normal thought processes to the point that, for example, they cannot cast aside negative thoughts or feelings.

“Depression is like gridlock in the brain’s networks,” says Dr. Jonathan Downar, a psychiatrist at Toronto Western Hospital who also has a doctorate in neuroimaging.

He and his research team essentially use magnetic pulses – rTMR – to unclog the gridlock.

“This is the third arm of psychiatry,” Downar says. “It’s not meds and it’s not therapy, it’s fixing the circuits in the brain.”

The treatment is pretty simple. First, the patient undergoes a functional MRI (magnetic resonance imaging) that maps the brain and its neural activity.

A technician, using the fMRI as a guide, then targets specific regions of the brain where the gridlock-causing-depression is located, and blasts them with magnetic pulses. The treatment isn’t painful – it feels like an elastic being snapped against your head – and it has virtually no side effects, and it’s pretty effective.

After a standard treatment (38 minutes a day for six weeks), about one-third of patients go into remission (meaning their depression lifts completely) and another 50 per cent see their symptoms diminished by half. The remaining 20 per cent see no benefit.

The idea of treating depression with magnetic pulses has been around since the 1980s. The rTMS procedure itself was approved by Health Canada in 2002 and it’s used (and paid for under medicare) in two provinces, Quebec and Saskatchewan.

But the treatment protocol is cumbersome (hence expensive) and because it works about half the time, it’s a bit of a crapshoot.

“rTMS is pretty good – more effective than drugs for treating severe depression – but we need more remission,” Downar says. “And we need to be able to treat more people and bring down the cost.”

So he has made improving access – and bringing down the cost – the focus of his research, and that’s what is getting the attention of policy-makers and patients alike.

“Quebec currently pays $175 for each rTMS treatment. We want to get that down to $40,” Downar says. “We also want to get the duration of treatment down to two weeks from six.”

That’s happening thanks to some research-driven innovations in treatment.

There is currently research under way – funded by the Ontario Brain Institute – to see if treatment times can be reduced to three minutes from 38 minutes, and the preliminary results are promising. (The efficiency comes from using a more refined magnetic pulse that more accurately mimics what goes on in the brain.)

Second, instead of giving patients one treatment a day, the shorter sessions allow them to receive five treatments a day. The good news is that a more intense two-week course of treatment gives results that are just as good as the lengthier one.

The final piece of the puzzle is making the treatment itself more effective. To do that, researchers are targeting a different part of the brain – the dorsal nexus instead of the left frontal lobe, long thought to be the source of depression.

The research team is also studying the MRIs of patients to see who responds best to treatment based on their brain activity.

Downar is convinced that, by implementing the innovations that arose from research, the approach can be made efficient and cost-effective for treating severe depression.

He hopes that, in the years to come, rTMS machines will be standard in all psychiatric clinics and psychiatrists’ offices. “It won’t replace drugs and it won’t replace therapy but it can help make them more effective and ensure more people with major depression get help.”

The treatment is not a cure – severe depression tends to be a relapsing illness – but “booster shots” appear to be effective.

There are also tantalizing clues that rTMS can work well to treat post-traumatic stress disorder (PTSD), obsessive-compulsive disorder (OCD) and eating disorders like bulimia.

“The whole purpose of my research is to make this a no-brainer,” Downar says. “It’s not good enough for us to make theoretical improvements. We have to improve access and care for patients.”

Follow on Twitter: @picardonhealth

 

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