About 1 in 5 Canadians with major depressive disorder has treatment-resistant depression (TRD), which historically has been defined as the failure to respond to two or more adequate trials of pharmacologic therapy.

Canadians with TRD have reported frustration over their difficulty in accessing mental health services. Almost two thirds of these patients ultimately present to the emergency room, sometimes multiple times. However, Ontario has joined Alberta and Saskatchewan in offering patients with TRD (aged 18 years or older) access to a publicly funded, repetitive transcranial magnetic stimulation (rTMS) program. The program was announced by the Centre for Addiction and Mental Health (CAMH) on July 8.

“Until now, there has not been a coherent way of delivering rTMS,” Daniel Blumberger, MD, scientific director of the Temerty Centre for Therapeutic Brain Intervention at CAMH in Toronto, told Medscape News Canada. Blumberger is also the provincial clinical lead of the Neurostimulation Procedures Program at Ontario Health’s Mental Health and Addictions Centre of Excellence in Toronto.

“As a result, there haven’t been the resources to properly staff available devices,” he said. Ontario’s rTMS program “is a major milestone. It opens access broadly across the province.” CAMH will support 18 rTMS devices at 15 sites across Ontario and provide access to effective treatment for roughly 2250 people with TRD annually. 

What Is rTMS?

The therapy “is an interventional psychiatry approach to treating difficult-to-treat neuropsychiatric conditions,” Peter Giacobbe, MD, inaugural Kerr Chair in Interventional Psychiatry and clinical head of the Harquail Centre for Neuromodulation at Sunnybrook Health Sciences Centre in Toronto, told Medscape News Canada. “It involves the application of magnetic pulses through the scalp and skull to stimulate the brain. It’s a biological but nonpharmacological option for TRD,” he said.

Although many patients with depression respond to conventional treatments, a significant proportion does not, Giacobbe noted. In addition, some patients experience significant side effects while taking pharmacologic therapy.

“The side effect profile of TMS is different from that of medication; it can offer support and symptom relief in ways medications won’t,” Giacobbe told Medscape News Canada.

Research has shown that rTMS is well tolerated. Roughly 10% of patients discontinue treatment early, which is on par with the discontinuation rate associated with antidepressants. “The vast majority of people experience some discomfort at the site of stimulation, and time-limited, mild headaches are fairly common — affecting about 30% to 50% of patients,” said Blumberger.

“I’ve had it done on myself when I’m training students,” said Giacobbe. “It feels like static electricity. But everyone’s pain sensitivity and threshold can differ, and discomfort (which can be worked through by changing the energy level within certain ranges of the position of the pulses) is the most common reason for discontinuation,” he said. “We also counsel people to take anti-inflammatories before they come in.”

Life-Changing Therapy

In its announcement, CAMH characterized rTMS as “life-changing” for many. It’s not a new therapy by any means. Health Canada approved its use for TRD in 2002. Clinical trials and registry-based outcomes data have shown that, on average, about 50% of patients achieve a meaningful reduction in symptoms, which Blumberger said translated into improvement in depressive symptoms and quality of life. Roughly one third of patients achieve remission, which can last for months or years.

Ontario’s current program offers five covered rTMS protocols, Giacobbe explained. Each session involves a 3-minute application of rTMS in an outpatient facility during a consultation that lasts roughly 30 minutes. Treatment is administered five times weekly over 6 weeks, although faster regimens are being studied. Patients with worsening symptoms at 4 months or more after the 6-week protocol can access another treatment course.

Referring Patients

CAMH is coordinating the provision of rTMS for Toronto-region sites, which include CAMH, University Health Network, St. Michael’s Hospital, and Sunnybrook Health Sciences Centre. A list of rTMS networks throughout the province, along with referral information (including patient inclusion and exclusion criteria), can be found on the Ontario Health website. 

One of the most important things that referring physicians, nurse practitioners, or psychiatrists might wish to convey to their patients is that rTMS is not the same as electroconvulsive therapy (ECT), said Giacobbe. Though rTMS and ECT involve stimulating the brain with magnetic pulses and have been used successfully in TRD, ECT is distinct in that it requires anesthesia, involves a controlled seizure, and carries cognitive side effects. 

None of these things are associated with rTMS, which “occupies the space between medications and ECT,” said Giacobbe. “Data from Boston’s Massachusetts General Hospital suggest that if you try rTMS earlier on, after failing one or two treatments, it is superior to some antipsychotics, which are typically used for augmentation. Think of this as a bona fide option earlier rather than later to get the best results for your patients.” He added that “to extend access is really a game-changer for patients in our province.”

Blumberger and Giacobbe reported having no relevant financial relationships. 

Liz Scherer is an independent medical/health journalist who frequently reports on Canadian and European health news.